Multiple choice general knowledge math & puzzles

A man can row 5 kmph in still water. If the river is running at 1kmph, it takes him 75 minutes to row to a place and back. How far is the place?

  1. 3

  2. 6

  3. 9

  4. 12
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Downstream speed = 5 + 1 = 6 kmph. Upstream speed = 5 - 1 = 4 kmph. Total time = d/6 + d/4 = 5d/12 hours. Given 5d/12 = 75 minutes = 1.25 hours, so d = 3 km. The answer checks out: 3/6 + 3/4 = 0.5 + 0.75 = 1.25 hours.

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