# Boats and Streams

1. A boat can travel 144 km upstream in 12 hrs and the same distance downstream in 6 hrs. In how many hours a boat can travel 360 km in both upstream and downstream? (In hrs)

A) 56    B) 39  C) 28    D) 45    E) 50

Sol: Speed of the boat = x

speed of the stream = y

upstream speed = x − y

downstream speed = x + y

Ans: D

2. A boat can travel 16 km downstream in 24 mins. The speed of the water current is 6.5 kmph. The boat takes 201 minutes to travel from point A to B and return to point A. What is the distance between points A and B? (In km)

A) 42   B) 36   C) 67    D) 54    E) 48

= 40 km/hr

x + y = 40 km/hr

current speed x = 6.5 km/hr

boat speed y = 33.5 km /hr

Ans: D

3. The speed of the boat in still water is 9 kmph more than the speed of the current. If total time taken by boat to travel 30 km downstream and 36 km upstream is 6 hours, what is the speed of the current? (In kmph)

A) 4.5   B) 2.5    C) 2    D) 3    E) 4

Sol: boat speed : current speed

Current speed = 3 kmph

Ans: D

4. The speed of the boat downstream is 350% more than the speed of the boat upstream. The distance covered by the boat was 270 km downstream and 120 km upstream in 18 hrs, then find the time taken by boat to cover a distance of 275 km in still water?

A) 13    B) 10    C) 15    D) 12    E) 16

Sol: Upstream speed : Downstream speed

100x    :     450x

2x    :        9x

x = 5

upstream speed = 2x = 10

downstream speed = 9x = 45

Speed of boat in still water

5. Speed of man in still water is 30 kmph and the river is running at 18 kmph. The total time taken to go a place and comeback is 25 hrs. Find the total distance travelled by the man. (In km)

A) 480    B) 360    C) 180    D) 200    E) 240

Total distance = d + d = 480 km

Ans: A

6. Boat ‘A’ can travel 30 km upstream in 1 hour 40 minutes, when the speed of the river current is 3.5 kmph. How much distance can boat ‘B’ cover in 2 hours 36 minutes while travelling downstream, if its speed in still water is 5 kmph less than boat A’s speed in still water? (Considering that the speed of the current is the same) (In km)

A) 46    B) 48    C) 58    D) 56    E) 52

x − y = 18 kmph

current speed (y) = 3.5 kmph

then speed of boat A (x) = 21.5

speed of boat B = 21.5 − 5 = 16.5

distance travelling by the boat B

Ans: E

7. A boat can travel 5.1 km upstream in 17 minutes. It can travel 14.8 km downstream in 37 minutes. What is the speed of the boat in still water? (In kmph)

A) 22    B) 23    C) 20    D) 13    E) 21

8. A boat takes 576 minutes to travel from point x to y and then come back to point x. The distance between point x and y is 84 km. If the respective ratio of speed of the boat in still water and speed of water current is 6 : 1, what is the speed of the boat downstream? (In kmph)

A) 15    B) 21    C) 18   D) 24    E) 12

Sol:  speed of boat = 6x

speed of current = 1x

Ans: B

9. The speed of a boat in still water is 15 kmph and the speed of the current is 3 kmph. The distance travelled by the boat from point P to point Q downstream is 15 km more than the distance covered by the same boat from point Q to point R upstream in the same time. How much time will the boat take to travel from R to Q downstream?

A) 1 hr 40 mins    B) 1 hr 36 mins    C) 2 hrs 15 mins   D) 2 hrs 24 mins    E) 3 hrs

Sol: let distance between Q and R = x

distance between P and Q = x + 15

10. A boat covers a distance of 60 km in 3 hrs in downstream. If speed of stream is 5 kmph, then find time taken by boat to cover 45 km in upstream and 60 km in downstream?

A) 5.5 h    B) 7.5 h    C) 9 h    D) 11.5 h   E) 12 h

x + y = 20 kmph

stream speed (y) = 5 kmph

x + 5 = 20

x = 15 kmph (boat speed)

Ans: B

11. The respective ratio between the speeds of the boat in still water to upstream is 7.5 : 7. The distance covered by the boat downstream in 2 hours is 56 km, then find the distance covered by the boat upstream in 2 hrs 36 minutes. (In km)

A) 63.7   B) 47   C) 92    D) 49   E) 50.1

Sol: x : x − y

7.5 : 7

15x 14x speed of the stream (y) = 15x − 14x = 1x

downstream speed (x + y) = 16x

16x → 28 kmph

14x → ?

Upstream speed (x − y) = 24.5 kmph

Ans: A

12. Ashok can swim at speed of 18 kmph in still water and the speed of the stream is 40% of the speed of Ashok in downstream. If he swims to a certain point and comes back in 14 hr, then find the total distance covered by Ashok in downstream and in upstream together? (In km)

A) 160    B) 180    C) 90   D) 140    E) 110

Sol: boat speed = x

stream speed = y

downstream speed = x + y

upstream speed = x − y

13. The respective ratio between the speed of the boat in still water and the stream is 4 : 1. The distance covered by the boat downstream in two hours is 45 km. Find the time taken by boat to cover 54 km downstream.

A) 18 kmph    B) 24 kmph    C) 21 kmph    D) 16 kmph    E) 28 kmph

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Posted Date : 28-02-2023

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