# Boats & Streams Tricks & Tips Part

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**Terms Related To Boats And Sreams:**

** Speed of the boat:**It refers to the velocity of the boat in standing water ,let it be **X**.

** Speed of the Stream**: It refers to the velocity at which the water flows,let it be **Y**.

** Upstream Speed (U):** It is expressed as the (Speed of the Boat – Speed of the Stream) =**X-Y**. They row the boat in the opposite direction to the flow of the stream.

** Downstream Speed (D)**: It is expressed as the (Speed of the Boat + Speed of the Stream) =**X+Y.** They Row along the flow of Stream.

** Speed** of the boat in **still water **when upstream and downstream speed is given=**1/2(D+U)**

__All about Boats and Streams – Types and Essential Tips:__

Dear Aspirants, Here we have given the important points that you have to remember while solving boats and streams problems and its types. Definitely this is will help you, make use of it.

__Introduction:__

If the water is not moving then it is called still water.**Still Water:**Moving water of the river is called stream.**Stream:**If a boat or a swimmer moves in the opposite direction of the stream then it is called upstream.**Upstream:**If a boat or a swimmer moves in the same direction of the stream then it is called downstream.**Downstream:**

__Points to remember:__

- When speed of boat or a swimmer is given then it normally means speed in still water.
- If speed of boat or swimmer is x km/h and the speed of stream is y km/h then,
- Speed of boat or swimmer upstream = (x − y) km/h
- Speed of boat or swimmer downstream = (x + y) km/h

iii. Speed of boat or swimmer in still water = 1/2(Downstream + Upstream)

- Speed of stream = 1/2(Downstream – Upstream)

__Types of problems:__

** 1.**A man can row certain distance downstream in t1 hours and returns the same distance upstream in t2 hours. If the speed of stream is y km/h, then the speed of man in still water is given by

**= y×(t2 + t1) / (t2 – t1)**

** 2.**A man can row certain distance downstream in t1 hours and returns the same distance upstream in t2 hours. If the speed of stream is y km/h, then the speed of man instill water is given by

**= y× (t2 – t1) / (t2 + t1)**

** 3.**A man can row in still water at x km/h. In a stream flowing at y km/h, if it takes ‘t’ hours to row to a place and come back, then the distance between two places is given by

**= [t× (x ^{2} – y^{2})]/(2 × x)**

** 4.**A man can row in still water at x km/h. In a stream flowing at y km/h, if it takes t hours more in upstream than to go downstream for the same distance, then the distance is given by

**= [t× (x ^{2} – y^{2})]/(2×y)**

** 5.**A man can row in still water at x km/h. In a stream flowing at y km/h, if he rows the same distance up and down the stream, then his average speed is given by

**= (x ^{2} – y^{2})/x**

** 6.**A man can row a distance ‘D’ upstream in t1 hrs and he rows the same distance down the stream in t2 hrs then speed is given by

**Stream speed = [D×(t1-t2)]/(2×t1×t2)**

** 7.**A man can row a distance ‘D’ upstream in t1 hrs. and he rows the same distance down the stream in t2 hrs. then speed is given by

**Man speed = [D×(t1+t2)]/(2×t1×t2)**

### #.1 TYPE 1:

### BASED ON TIME, SPEED AND DISTANCE:

**A boat can travel with a speed of 13km/hr in still water. If the speed of the stream is 4km/hr.Find the time taken by the boat to go 68km downstream?**

Speed of the boat in still water(X)=13km/hr,

Speed of the stream(Y)=4km/hr.

Relative Speed of the boat in downstream=X+Y 17km/hr

** Time=Distance/Speed**

**Time**=68/17=**4hrs**

** 2.A motorboat ,whose speed is 15km/hr in still water goes 30 km downstream and comes back in a total of 4hrs30mins.The speed of the stream in(km/hr)?**

Speed of the Boat in Still Water(X)=15km/hr,

Time T=4hr 30min(for DownStream+UpStream)

Let the speed of the Stream=Y.

DownStream Speed=Speed of Boat +Speed of the Stream

=15+Y

UpStream Speed=Speed of the Boat-Speed of the Stream

=15-Y

** Time =Distance/Speed**

Time =4hr 30min=9/2hr

(9/2)=(30/(15+Y) + 30/(15-Y))

9/2=900/(225-Y^2)

**Y=5**

**Speed of the Stream=5km/hr.**

**#.2 TYPE 2:**

**BASED ON RATIO:**

**1.A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat in still water and the stream is?**

Let the man’s upstream speed be X

Man’s downstream speed be 2x

**Speed** of the boat in **still water **when upstream and downstream speed is given=**1/2(D+U) Speed **of the stream =**1/2(D-U)**

Speed of the Boat |
Speed of the Stream |

=½(2X+X)=3X/2
=3 |
½ (2X-X)=X/2
1 |

The ratio between speed of the boat to the speed of the stream=**3:1**

### #.3 TYPE 3:

### BASED ON EFFICIENCY:

**1.A man can row 12km/hr in still water .He finds that it takes him thrice as much time to row up the river as it takes to row down the river.What is the speed of the current?**

Let the distance be D,

Speed of the boat in still water=12km/hr.

Speed of the current=Ykm/hr

Time taken during Upstream | Time taken during downstream |

3 | 1 |

Distance =Time *Speed

upstream=3*(12-Y){ Speed of the Boat – Speed of the Stream}

Downstream=1*(12+Y){ Speed of the Boat +Speed of the Stream}

Distance is same here

3*(12-Y)=12+Y

36-3Y=12+Y

4Y=24

Y=6km/hr

**Speed of the Stream=6km/hr**

### # 4.TYPE 4:

### SOLVING BY EQUATIONS:

**1.A person can row 18km downstream and 27km upstream in three hours and 18km upstream and 27km downstream in 2hours 42minutes.What is the upstream and Downstream Speed?**

Downstream D=X+Y Upstream U=X-Y

Therefore,

18D+27U=3

27D+18U=27/10

Solving above we get U=2/25 and D=14/300

### # 5.TYPE 5:

### BASED ON AVERAGES:

**1.A Man can row at a speed of 5km/hr in still water to a certain distance upstream and back to the starting point in ariver,which flows at 2km/hr.Find the average speed for the total journey?**

Average when 2 speeds are given for travelling the same distance too and fro then the average speed =2DU/(D+U)

Where D=Speed when travelling Downstream,U=Speed when travelling Upstream.

Downstream Speed=Speed of the Boat + Speed of the Stream .D=5+2=7km/hr

Upstream Speed =Speed of the Boat – Speed of the Stream.U=5-2=3km/hr

Average Speed=2*7*3

2*7*3 42 |

3+7 10 |

4.2km/hr

**1)A Man can row 60km Upstream & 88 km downstream in 20 hours.Also,he can row 80km upstream and 110km downstream in 26 hours.Find the rate of the current and the speed of the man in still water?**

These type of Problems can be just solved by forming equation,You have to Remember only one thing that,**Upstream Speed=1/x and Downstream Speed=1/y**

Given that,

**60U + 88D=20**

**80U+110D=26**

Since U=1/X & D=1/Y

X=5.Y=11

Therefore,

Rate in Still Water=(Upstream Speed+DownStream Speed)/2

=(11+5)/2

=16/2

**Rate in StillWater=8Km/hr**

Rate of Current=(11-5)/2

=6/2

**Rate Of Current=3Km/hr**

**2)City A and B were 600 km Apart.Meenesh live in City A & Mithesh live in City B.The River flows at the rate of 5 km/hr.Meenesh can row a boat at the rate of 25km/hr in still water at the same time Mithesh can row a boat at the rate of 15km/hr in Still water.Find at what time they meet for the first time & Second Time?**

**Given that,**

The Cities where 600 Km Apart,

Speed of Meenesh in Still water=25km/hr

Speed of Mithesh in Still water=15km/hr

Speed of Stream=5 km/hr

**SPEED OF MEENESH:**

DownStream Speed=Speed of Still Water + Speed of Stream =25 + 5 =30 km/hr

UpStream Speed=Speed of Still Water -Speed of Stream=25 -5=20 km/hr

**SPEED OF MITHESH**:

DownStream Speed=15+5=20km/hr

UpStream Speed=15-5=10km/hr

**Meenesh & Mithesh will Meet for the First Time:**

Here the Distance =600kms

Relative Speed=25+15=**40km/hr**

Have you Remembered ,what we had written here,

**To Cross Each Other when they travel in the Opposite Direction,**

=Distance/Relative Speed

=600 km/Relative Speed

When they travel in Opposite Direction their Speeds should be Sum up

When they travel in Same Direction their Speeds should be Subtracted.

=600/40(Because they were travelling in Opposite Direction)

=**15 hours**

**They will meet Each Other after 15 hours of their journey**

**Their Second Meet:**

Meenesh would Reach City B :

Time=Distance/Speed

=600/(25+5)[Downstream Speed=Speed in Still Water+Speed of Stream]

=600/30

**=20hours**

**Meenesh Reach City B after 20 hours**

At the same time Mithesh would Reach,

Distance travelled by Mithees=Time*Speed

=20 hours*(15-5)[Because Mithesh is travelling Upstream]

=20*10=**200 km**

Now,Friends When Meenesh in City B,Mithesh is 200 km ahead of City B.

What is the distance between them,

=200Km,

Speed of Meenesh =25-5=20km/hr(Upstream Speed=Speed in Still Water-Speed of Stream)

Speed of Mithesh=15-5=10km/hr

Relative Speed=200/(20-10)

=200/10

**=20hours**

They will meet for the Second time at 20+20=**40hours**

### Shortcut Tricks to Solve Boats and Streams Questions

### INTRODUCTION:

** Downstream: **If the boat is moving in the direction of the stream.

**If the boat is moving in the direction opposite to the direction of the stream.**

__Upstream:__Assume the speed of the boat in still water as: ‘b’ kilometres per hour (kmph).

Take the speed of the stream as: ‘s’ kmph.

Hence ** Aggregate Downstream Speed** =

**b + s kmph**. (Boat is moving with the steam of water).

** Upstream Net Speed** =

**b – s km/hr**. (Boat is moving against the direction of the stream).

__Speed of Boat in Still Water: __**½ (Downward Speed + Upward Speed) **

__Proof of Basic Formula__

**½ (Downstream Speed + Upstream Speed) = ½ [b + s + (b-s)] = ½ (2b) = b**

(Proved as per the assumption)

__Speed of Stream:__** ½ (Downward Speed – Upward Speed)**

__Proof of Basic Formula __

**½ (Downward Speed – Upward Speed) = ½ [b + s – (b-s)] = ½ [b + s – b + s] = ½ (2 s} = s**

(Proved as per the assumption).

__ ALWAYS REMEMBER: __

- Speed of boat is always greater than the speed of the stream.
- Downstream speed is always greater than the upward speed.

## EXAMPLES:

**Example 1. **

**A man can row a boat @ 9 kmph in still water. He takes double the time to move upstream than to move the downstream – the same distance. Find the speed of the stream.**

#### Solution:

**ATQ (According to Question) and formula given above:**

→Let the downward time = 1 hour and so the upward time = 2 hours.

→1/9+s = 2/9-s (Since distance is the same)

→18 + 2 s = 9 – s (By cross multiplication)

→18 – 9 = s + 2 s

→9 = 3 s

Hence s or Speed of stream = 9/3 = **3 kmph Answer.**

**OR **

Simply

→b + s = 2(b –s)

→i.e. b + s = 2b – 2s

→i.e. s + 2s = 2b –b

**Or **

→b = 3s or 9 = 3s (b = 9 is given) = 3 kmph Answer

### Example 2.

**A boat runs at 20 kmph along the stream and 10 kmph against the stream. Find the ratio of speed of the boat in still water to that of the speed of the stream. **

#### Solution:

→ ATQ (According to Question) and formula given above:

→ Speed of Boat = ½ (20 + 10) = 15 kmph.

→ Speed of Stream = ½ (20 – 10) = 5 kmph.

→ Ratio: 15:5 = **3:1 Answer. **

### Example 3.

**Find the time taken by the boatman to row 4 kilometres downstream and return to his starting point, if the speed or rate of stream is 2 kilometres per hour and the speed of the boat is 6 kilometres per hour. **

#### Solution:

**ATQ (According to Question) and formula given above: **

→ Time = Distance/Speed

→ Time taken = 4/6+2 + 4/6-2 = 4/8 + 4/4 = 0.5 + 1 = **1.5 Hour**.

### Example 4.

**If the speed of the stream is 2 km per hour, and the speed of the boat in still waters is 10 km per hour then find the time taken to cover 60 kms downstream.**

#### Solution:

→ ATQ (According to Question) and formula given above:

→ 60/10+2 = 60/12 = **5 hours Answer. **

### Example 5.

**Find the speed of the stream when a boat takes 5 hours to travel 60 kms downstream at a rate of 10 kms per hour in still water. **

#### Solution:

**ATQ (According to Question) and formula given above: **

→ Speed b + s = 60/5 = 12 kmph

→ Speed b = 10 kmph

→ So, speed s = 12-10 = **2 kmph Answer. **

### Example 6.

**A boat covers a certain distance in one hour downstream with the speed of 10 kmph in still water and the speed of current is 4 kmph. Then find out the distance travelled. **

#### Solution:

**ATQ (According to Question) and formula given above:**

→ Distance = Speed x Time = 1 x (10+4) = **14 kms. Answer**

Example 7.

**A boat takes 6 hours to cover 36 km downstream and 8 hours to cover 32 km upstream. Then the speed of the boat in still water is? **

#### Solution:

**ATQ (According to Question) and formula given above: **

→ Speed of Boat = ½ (36/6 + 32/8) = ½ (6+4) = ½(10) = **5 kmph Answer. **

### Example 8.

**A boat takes 6 hours to cover 36 km downstream and 8 hours to cover 32 km upstream. Then the speed of the stream is? **

#### Solution:

**ATQ (According to Question) and formula given above:**

**→** Speed of Stream ½ (36/6 – 32/8) = ½ (6-4) = ½ (2) = **1 kmph Answer.**

### Example 9.

**If a man rows 6 km downstream in 3 hours and 2 km upstream in 2 hours then how long will he take to cover 9 kms in stationary (still) water?**

#### Solution:

**ATQ (According to Question) and formula given above: **

→ Speed of Boat in still waters = ½ (6/3 + 2/2) = ½ (2 + 1) = 1.5 kmph

→ Time taken for 9 kms = 9/1.5 = **6 hours Answer**

**1) A man can row 18km/hr in still water. speed of the man in downstream is thrice the speed in upstream. Find the rate of stream.**

Solution:

Let, Speed of man in upstream a = a

Speed of man in downstream b = 3a

Speed of man in still water u = ½(a + b)

Speed of man in still water = ½(3a + a) = 2a

We know speed of man in still water = 18

So, a = 9

Rate of stream = ½(27 – 9) =9 km/hr

**2) A boat can cover certain distance in downstream in 1hr. and it takes 1½hr to cover same distance in upstream. If speed of the stream is 3kmph, then what will be the speed of boat?**

Solution:

let speed of boat in still water be x

speed in downstream = x + 3

speed in upstream = x – 3

Since boat covered same distance in upstream and downstream,

(x + 3)*1 = (x – 3)*(3/2)

speed in downstream x= 15 kmph

**3) A man can row three quarter of a km against the stream in 11¼ min and down the stream in 7½min. what is the speed of man in still water.**

Solution:

Speed of man in Upstream = ((¾)/(45/4)) *60

= 4 kmph

Speed of man in Downstream = ((¾)/(15/4))* 60

= 12 kmph

Speed of man in still water u = ½(a + b)

Speed of man in still water = (12 + 4)*½ = 8 kmph

**4) A streamer takes 3hr to cover a distance of 24km upstream, if the rate of stream is 3 kmph. Then find the speed of streamer in still water.**

Solution:

Upstream speed = 24/3 =8kmph

Rate of stream = 3kmph

Speed of streamer – rate of stream = upstream

Speed of streamer = 11kmph

**5) The distance between two points is 36km. A boat rows in still water at 6kmph, it takes 8hr less to cover dist in downstream in comparison to that in upstream. Find the rate of stream.**

Solution:

Time = distance * speed

Difference between time taken to cover upstream and downstream is 8hr

(36/(6-x)) – (36/(6+x)) = 8

36(6+x) – 36(6-x) = 8(36-x^{2})

9x = 36- x^{2}

x^{2}+9x-36 = 0 (to find value of x use quadratic equation technique)

(x+12)(x-3)=0

Speed cannot be negative so x = 3kmph

Rate of stream = 3kmph

### Types of Questions asked in Previous Exam

**Type 1**: When the distance covered by boat in downstream is same as the distance covered by boat upstream. The speed of boat in still water is x and speed of stream is y then ratio of time taken in going upstream and downstream is,

Short Trick:

**Time taken in upstream** : **Time taken in Downstream** = (x+y)/(x-y)

**Example: **

A man can row 9km/h in still water. It takes him twice as long as to row up as to row down. Find the rate of the stream of the river.

**Solution:**

Time taken in upstream : Time taken in Downstream = 2 : 1

Downstream speed : Upstream speed = 2 : 1

Let the speed of man = B, & speed of stream = S

B + S : B – S = 2/1

By using Componendo & Dividendo

B/R = 3/1, R = B/3

R = 9/3 = 3km/h

**Type 2: **A boat cover certain distance downstream in t_{1} hours and returns the same distance upstream in t_{2} hours. If the speed of stream is y km/h, then the speed of the boat in still water is:

Short Trick:

Speed of Boat = y [(t_{2} + t_{1}) / (t_{2} – t_{1})]

**Example**

A man can row certain distance downstream in 2 hours and returns the same distance upstream in 6 hours. If the speed of stream is 1.5 km/h, then the speed of man in still water is

**Solution:**

By using above formulae

= 1.5 [(6+2) / (6-2)] = 1.5 * (8/4) = 1.5 * 2 = 3km/h

**Type 3: **A boat’s speed in still water at x km/h. In a stream flowing at y km/h, if it takes it t hours to row to a place and come back, then the distance between two places is

Short Trick: **Distance** = [t*(x^{2} – y^{2})]/2x

**Example**

A motor boat can move with the speed 7 km/h. If the river is flowing at 3 km/h, it takes him 14 hours for a round trip. Find the distance between two places?

**Solution: **By using above formulae

** = **[14 * (7^{2} – 3^{2})]/2* 7 = [14 * (49-9)]/2*7

= 14*40/2*7 = 40km

**Type 4: ** A boat’s speed in still water at x km/h. In a stream flowing at y km/h, if it takes t hours more in upstream than to go downstream for the same distance, then the distance is

Short Trick: **Distance** = [t*(x^{2} – y^{2})]/2y

**Example**

A professional swimmer challenged himself to cross a small river and back. His speed in swimming pool is 3km/h. He calculated the speed of the river that day was 1km/h. If it took him 15 mins more to cover the distance upstream than downstream, then find the width of the river?

**Solution: **By using the above formulae

Distance = [t*(x^{2} – y^{2})]/2y

= [(15/60) (3^{2} – 1^{2})]/2*1

= [(1/4) * 8] / 2

= 2/2 = 1 km.

** **

**Type 5: **A boat’s speed in still water at x km/h. In a stream flowing at y km/h, if it cover the same distance up and down the stream, then its average speed is

Short Trick: **Average speed** = upstream * downstream / man’s speed in still water

**Note: **The average speed is independent of the distance between the places.

**Example**

Find the average speed of a boat in a round trip between two places 18 km apart. If the speed of the boat in still water is 9km/h and the speed of the river is 3km/h?

**Solution:** Average speed = upstream * downstream / man’s speed in still water

Average speed = 6 * 12 / 9 = 8km/h

# Problem Set For Boat & Stream

**A boat takes 28 hours for travelling downstream from point A to point B and coming back to point C midway between A and B. If the velocity of the stream is 6km/hr and the speed of the boat in still water is 9 km/hr, what is the distance between A and B?**

A.115 km

B.120 km

C.140 km

D.165 km

E.150 km**Speed of a man in still water is 5 km/hr and the river is running at 3km/hr. The total time taken to go to a place and come back is 10 hours. What is the distance travelled?**

A.10 km

B.16 km

C.24 km

D.32 km

E.36 km**A boat running upstream takes 9 hours 48 minutes to cover a certain distance, while it takes 7 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?**

A.5:2

B.7:4

C.6:1

D.8:3

E.2:5**A boat can travel 20 km downstream in 24 min. The ratio of the speed of the boat in still water to the speed of the stream is 4 : 1. How much time will the boat take to cover 15 km upstream?**

A.20 min

B.22 min

C.25 min

D.30 min

E.35 min**A boat whose speed in 20 km/hr in still water goes 40 km downstream and comes back in a total of 5 hours. The approx. speed of the stream (in km/hr) is:**

A.6 km/hr

B.9 km/hr

C.12 km/hr

D.16 km/hr

E.18 km/hr**A boat covers a certain distance downstream in 2 hour, while it comes back in 2 1/2 hours. If the speed of the stream be 5 kmph, what is the speed of the boat in still water?**

A.40 kmph

B.30 kmph

C.35 kmph

D.45 kmph

E.None of these**A boat running downstream covers a distance of 40 km in 5 hrs and for covering the same distance upstream it takes 10 hrs. What is the speed of the stream?**

A.5 km/hr

B.2 km/hr

C.6 km/hr

D.4 km/hr

E.3 km/hr

**A boat goes 4 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 15 km in stationary water?**

A.2 hour 15 min

B.2 hour

C.3hr

D.3hr 30 min

E.None of these**A man rows to a place 40 km distant and come back in 9 hours. He finds that he can row 5 km with the stream in the same time as 4 km against the stream. The rate of the stream is:**

A.1 km/hr

B.1.5 km/hr

C.2 km/hr

D.2.5 km/hr

E.None of these**A man can row 8 km/hr in still water. When the river is running at 4 km/hr, it takes him 2 1/3hr to row to a place and come back. How far is the place?**

A.4 km

B.5 km

C.7 km

D.10 km

E.None of these

**If Nishu can swim downstream at 6kmph and upstream at 2kmph.What is his**A.5 km/hr

speed in still water ?

B.4 km/hr

C.8km/hr

D.7km/hr**Ashok can row upstream at 8kmph and downstream at 12kmph.What is the**A.6km/hr

speed of the stream ?

B.3km/h

C.2 km/hr

D.4km/hr**A man rows 750m in 775 seconds against the stream and returns in 7**A.4.7km/hr

1/2 minutes. What is rowing speed in still water ?

B. 4km/hr

C.3.5km/hr

D.6km/hr**A man can row 9 (1/3) kmph in still water and finds that it takes him**A. 5km/hr

thrice as much time to row up than as to row down the same distance in the

river. What is speed of the current ?

B.3(1/2) km/hr

C.4 (2/3) km/hr

D.8 (3/2)km/hr**Sham can row a boat at 10kmph in still water. IF the speed of the**A.4 hours

stream is 6kmph, the time taken to row a distance of 80km down the stream

is

B.5hours

C.3 hours

D.2 hours**A boat takes 4hours for traveling downstream from point P to point**A.9 km

Q and coming back to point P upstream. If the velocity of the stream is 2km

ph and the speed of the boat in still water is 4kmph, what is the distance

between P and Q?

B.7 km

C.5 km

D.6km

**Speed of a boat in standing water is 9kmph and the speed of the**A.24 hours

stream is 1.5kmph. A man rows to a place at a distance of 10.5 km and

comes back to the starting point. Find the total time taken by him.

B.16 hours

C.20 hours

D.15 hours**A man rows to a place 48km distant and back in 14 hours. He finds**A.2 km/hr

that he can row 4km with the stream in the same time as 3km against the

stream. Find the rate of the stream.

B.1 km/hr

C.3 km/hr

D.3.5km/hr**There is road besides a river. Two friends started from a place P, moved to a shopping mall**A. Both

situated at another place Q and then returned to P again. One of them moves on a cycle at

a speed of 12 km/hr, while the other sails on a boat at a speed of 10 km/hr. If the river

flows at the speed of 4 km/hr, which of the two friends will return to place P?

B. Boater

C. Cyclist

D. None of these**A this usual rowing rate, Mohit can travel 12 miles downstream in a certain river in 6**A.2.5m/hr

hours less than it takes him to travel the same distance upstream. But if he could double

his usual rowing rate for his 24 miles round trip, the downstream 12 miles would then

take only one hour less than the upstream 12 miles. What is the speed of the current in

miles per hour?

B.4 m/hr

C.8/3 m/hr

D. 5/3m/hr

**A boat can travel 15 km downstream in 18 min. The ratio of the speed of the boat in still water to the speed of the stream is 4 : 1. How much time will the boat take to cover 10 km upstream?**

A) 22 min

B) 25 min

C) 20 min

D) 33 min

E) 30 min**Speed of a man in still water is 4 km/hr and the river is running at 2 km/hr. The total time taken to go to a place and come back is 4 hours. What is the distance travelled?**

A) 16 km

B) 13 km

C) 10 km

D) 6 km

E) 8 km**A boat takes 25 hours for travelling downstream from point A to point B and coming back to point C midway between A and B. If the velocity of the stream is 5 km/hr and the speed of the boat in still water is 10 km/hr, what is the distance between A and B?**

A) 100 km

B) 122 km

C) 146 km

D) 178 km

E) 150 km**A boat goes 6 km against the current of the stream in 2 hours and goes 8 km along the current in half hour. How long will it take to go 28.5 km in stationary water?**

A) 4 1/2 hours

B) 3 hours

C) 3 1/2 hours

D) 4 hours

E) None of these**A man can row 48 km upstream and 56 km downstream in 12 hrs. Also, he can row 54 km upstream and 70 km downstream in 14 hrs. What is the speed of man in still water?**

A) 4 km/hr

B) 10 km/hr

C) 12 km/hr

D) 15 km/hr

E) 18 km/hr**A boat takes 150 min less to travel 40 km downstream than to travel the same distance upstream. The speed of the stream is 4 km/hr. What is the downstream speed?**

A) 16 km/hr

B) 12 km/hr

C) 10 km/hr

D) 8 km/hr

E) None of these**A man rows to a place 40 km distant and back in a total of 18 hours. He finds that he can row 5 km with the stream in the same time as 4 km against the stream. What is the speed of boat in still water?**

A) 4.5 km/hr

B) 8 km/hr

C) 5.5 km/hr

D) 2 km/hr

E) None of these**In a stream running at 2 km/hr, a motorboat goes 6 km upstream and back again to the starting point in 2 hours. Find the speed of boat in still water.**

A) 9 km/hr

B) 12 km/hr

C) 8 km/hr

D) 10 km/hr

E) None of these**It takes five times as long to row a distance against the stream as to row the same distance in favor of the stream. What is the ratio of the speed of the boat in still water to that of stream?**

A) 7 : 4

B) 2 : 3

C) 9 : 5

D) 3 : 2

E) 5 : 2**A boat running downstream covers a distance of 32 km in 4 hrs and for covering the same distance upstream it takes 8 hrs. What is the speed of the stream?**

A) 5 km/hr

B) 2 km/hr

C) 6 km/hr

D 4 km/hr

E) 3 km/hr

**A boat can travel 4.2km upstream in 14min. If the ratio of the speed of the boat in still water to the speed of the stream is 7:1. How much time will the boat take to cover 17.6km downstream ?**

A)56min

B)44min

C)32min

D)48min

E)None of these**A man can row at 4 kmph in still water. If the velocity of the current is 1 kmph and it takes him 1 hour to row to a place and come back. how far is that place.**

A)1.8km

B)2.6km

C)1.5km

D)3.2km

E)None of these**Arun takes thrice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat in still water and stream is**

A)3:1

B)1:2

C)2:1

D)2:3

E)None of these**A boat takes 30 hours for travelling downstream from point A to point B and coming back to point C midway between A and B. If the velocity of the stream is 2 kmph and the speed of the boat in still water is 15 kmph, what is the distance between A and B?**

A)342km

B)356km

C)316km

D)308km

E)None of these**A boat takes 120min less to travel 30km downstream than to travel the same distance upstream.If the speed of the boat in still water is 8kmph then the speed of the stream is**

A)2kmph

B)8kmph

C)3kmph

D)4kmph

E)None of these**A boat running downstream covers a distance of 24km in 4hrs, while for covering**

**the same distance upstream it takes 6hrs, what is the speed of the boat in still water ?**

A)12kmph

B)10kmph

C)5kmph

D)7kmph

E)None of these**A man swims downstream 40 km in 5 hours and upstream 24 km in 2 hours. Find his speed in still water ?**

A)10kmph

B)15kmph

C)8kmph

D)12kmph

E)None of these**The speed of a boat in still water in 12 km/hr and the rate of current is 4 km/hr. The**

**distance travelled downstream in 12 minutes is**

A)3.2km

B)4.7km

C)5.1km

D)2.7km

E)None of these**A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along****the current in 10 minutes. How long will it take to go 5 km in stationary water?**

A)1.30hrs

B)3.209hrs

C)2.15hrs

D)1.25hrs

E)None of these**A boat goes 24 km upstream and 28 km downstream in 6 hours. It goes 30km upstream and 21 km downstream in 6 hours and 30 minutes. The speed of the boat in still water is**

A)10kmph

B)4kmph

C)6kmph

D)8kmph

E)None of these

**A man can row upstream at 10 km/hr and downstream at 16 km/hr. Find the man’s rate in still water and the rate of current.**

A. 13 km/hr, 3 km/hr

B. 10 km/hr, 2 km/hr

C. 3 km/hr, 13 km/hr

D. 15 km/hr, 5 km/hr**A boat can row at 16 km/hr in still water and the speed of river is 10 km/hr. Find the speed of boat with the river and speed of boat against the river.**

A. 13 km/hr, 3 km/hr

B. 15 km/hr, 5 km/hr

C. 26 km/hr, 6 km/hr

D. 6 km/hr, 26 km/hr**A man goes downstream 60 km and upstream 20 km, taking 4 hrs each. What is the velocity of current?**

A. 4 km/hr

B. 8 km/hr

C. 6 km/hr

D. 5 km/hr**A man rows downstream 28 km and upstream 16 km, taking 5 hrs each time. What is the velocity of current?**

A. 4 km/hr

B. 2.4 km/hr

C. 1.2 km/hr

D. 3 km/hr**A man can row 30 km upstream and 44 km downstream in 10 hrs. Also, he can row 40 km upstream and 55 km downstream in 13 hrs. Find the speed of the man in still water.**

A. 5 km/hr

B. 8 km/hr

C. 10 km/hr

D. 12 km/hr**A man can row 24 km upstream and 36 km downstream in 6 hrs. Also, he can row 36 km upstream and 24 km downstream in 6.5 hrs. Find the speed of the current.**

A. 2 km/hr

B. 8 km/hr

C. 10 km/hr

D. 12 km/hr**A man can row 6 km/hr in still water. When the river is running at 2 km/hr, it takes him 1 ½ hr to row to a place and come back. How far is the place?**

A. 2.5 km

B. 4 km

C. 5 km

D. 10 km**In a stream running at 2 km/hr, a motorboat goes 10 km upstream and back again to the starting point in 55 minutes. Find the speed (km/hr) of the motorboat in still water.**

A. 17

B. 20

C. 22

D. 25**A man can row a certain distance downstream in 2 hours and return the same distance in 6 hours. If the speed of current is 22 km/hr, find the speed of man in still water.**

A. 44km/hr

B. 48 km/hr

C. 50 km/hr

D. 55 km/hr**A man can row 9 3/5 km/hr in still water and he finds that it takes him twice as much time to row up than as to row down the same distance in river. The speed (km/hr) of the current is**

A. 2

B. 2 1/2

C. 3 1/5

D. 5

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