Boat and Stream MCQ Set 5

1. A man travels by a motor boat down a river to his office and back . With the speed of the river unchanged , if he doubles the speed of his motor boat , then his total travel time gets reduced by 75% . The ratio of the original speed of the motor boat to the speed of river is :

(a) √6 : √2

(b) √7 : 2

(d) 3 : 2

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Answer: B

2. A fisherman can row his boat to the market for 80 km along the stream . For this he takes 1 hours 20 minutes . His son says that , his father’s rowing speed in still water is 45 km/hr . How much time should he take to row the same distance back , against the stream ?

(a) 2 hrs 30 min

(b) 2 hrs 40 min

(d) 4 hrs

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Answer: B

3. Amit can row a boat d km upstream and the same distance downstream in 5 hours 15 minutes . Also , he can row the boat 2d km upstream upstream in 7 hours . How long will it take to row the same distance 2d km downstream for Amit?

(a) 3 hrs 15 min

(b) 3 hrs 30 min

(d) 4 hrs 10 min

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Answer: B

4. A man went downstream for 28 km in a motor boat and immediately returned . It tool the man twice as long to make the return trip . If the speed of the river flow were twice as high , the trip downstream and back would take 672 minutes . Find the speed of the boat in still water and the speed of the river flow .

(a) 8 km/hr , 2 km/hr

(b) 9 km/hr , 6 km/hr

(d) 9 km/hr , 3 km/hr

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Answer: D

5. A boat takes 38 hours for travelling downstream for point A to point B and coming back to point C midway between A and B . If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph , what is the distance between A and B ?

(a) 120 km

(b) 180 km

(d) 360 km

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Answer: D

6. Ravi can row a boat in still water in the speed of 14 km/h . If a river is flowing at the speed of 2 km/hr and Ravi takes 3 hours to cover a certain distance upstream then how much time will he take to cover the same distance downstream?

(a) 2 hr 20 min

(b) 2 hrs

(d) 2 hrs 30 min

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Answer: C

7. X , Y are two points in a river . Point P and Q divide the straight line XY into three equal parts . The river flows along XY and the time taken by a boat to row from X to Q and from Y to Q are in the ratio of 4 : 5 . The ratio of the speed of the boat downstream that of the river current is equal to :

(a) 3 : 10

(b) 3 : 4

(d) 4 : 3

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Answer: C

8. The speed of a boat in still water is 6 km/h and the speed of the stream is 1.5 km/h . In going from point A to point B and returning to A , the boatman takes 2 hours 40 min . Find the distance between points A and B .

(a) 7.5 km

(b) 7 km

(d) 8.5 km

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Answer: A

9. A man goes downstream with a boat to some destination and returns upstream to his original place in 5 hours . If the speed of the boat in still water and the stream are 10 km/hr and 4 km/hr respectively , the distance of the destination from the starting place is

(a)16 km

(b) 18 km

(d) 25 km

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Answer: C

10. A boat goes downstream in one third the time it takes to go upstream . Then , the ratio between the speed of boat in still water and that of the stream is :

(a) 3 : 1

(b) 1 : 3

(d) 2 : 1

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Answer: D