Multiple choice

In a river flowing at 2 kmph, a boat travels 48 km upstream and then returns downstream to the starting point. If its speed in still water is 6 kmph, find the total journey time.

  1. 15 hours

  2. 18 hours

  3. 12 hours

  4. 14 hours

  5. 16 hours
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Upstream speed = 6 - 2 = 4 kmph, time = 48/4 = 12 hours. Downstream speed = 6 + 2 = 8 kmph, time = 48/8 = 6 hours. Total = 12 + 6 = 18 hours. Speed in still water is the boat's own speed; current adds/subtracts from it.

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