Multiple choice

Rohit can row a boat 65Km upstream and 130Km downstream in 23 hours, whereas he can swim 45Km upstream and 104Km downstream in 17 hours. Find the speed of boat in still water and the speed of stream.

  1. 4 kmph, 9 kmph

  2. 8 kmph, 5 kmph

  3. 9 kmph, 4 kmph

  4. 5 kmph, 8 kmph

  5. 10 kmph, 3 kmph
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let boat speed = b, stream speed = s. Upstream = b-s, downstream = b+s. 65/(b-s) + 130/(b+s) = 23 and 45/(b-s) + 104/(b+s) = 17. Solving: b+s = 13, b-s = 5. Therefore b = 9 kmph, s = 4 kmph.

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