Multiple choice

A man takes four times as long to row up as to row down the river. If the rate of the river is 6 kmph, what is the rate of the man in still water?

  1. 5 km/h

  2. 8 km/h

  3. 10 km/h

  4. 12 km/h

  5. 15 km/h
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When rowing upstream, effective speed is (x - 6) kmph, and downstream it's (x + 6) kmph. Taking four times as long upstream means the upstream speed is one-fourth of downstream speed. Solving (x-6) = (x+6)/4 gives x = 10 kmph in still water.

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