Multiple choice

To cover a distance, time taken by a boat to go downstream is half of the time taken by the boat to go upstream. What is the ratio of the speed of the boat in still water and speed of current?

  1. 2: 1

  2. 1: 3

  3. 3: 1

  4. 1: 2

  5. 3: 8
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let boat speed = b and current speed = c. Downstream speed = b+c, upstream = b-c. Time ratio 1:2 means (b+c) = 2(b-c). Solving: b+c = 2b-2c, so 3c = b, giving ratio b:c = 3:1. The correct answer is 3:1.

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