In a fixed time, a boy swims double the distance along the current that he swims against the current. If the speed of the current is 3 km/hr, the speed of the boy in still water is

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In a fixed time, a boy swims double the distance along the current that he swims against the current. If the speed of the current is 3 km/hr, the speed of the boy in still water is

A6 km/hr

B9 km/hr

C10 km/hr

D12 km/hr

Answer:

B. 9 km/hr

Read Explanation:

Let the rate of swimming in still water be x kmph

Rate down-stream = (x + 3) kmph

Rate up-stream = (x – 3) kmph

According to the question,

$(x + 3) t = 2 (x-3)\times{t}$

x + 3 = 2x – 6

2x-x=3+6

x = 9 kmph

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