Multiple choice

Wasim rows a boat. He takes double the time to row the same distance while going upstream than going downstream. The ratio of the speed of the boat in still water and stream is

  1. 1 : 3

  2. 3 : 1

  3. 2 : 1

  4. 2 : 4

  5. 4 : 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let speed of boat = b, stream = s. Downstream speed = b+s, Upstream = b-s. Time = Distance/Speed. Time_up = 2 * Time_down. D/(b-s) = 2 * D/(b+s). b+s = 2b-2s. b = 3s. Ratio b:s = 3:1.

AI explanation

Let the speed of the boat in still water be B and the speed of the stream be S, meaning the downstream speed is (B + S) and the upstream speed is (B - S). Since the upstream time is double the downstream time for the same distance, the downstream speed must be double the upstream speed, giving B + S = 2(B - S). Solving this equation yields B + S = 2B - 2S, which simplifies to B = 3S. Therefore, the ratio of the speed of the boat in still water to the speed of the stream is 3 : 1.

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