Multiple choice

Manoj, the fisherman, bought a new motorboat which could travel in still water at 20 km/hr. He has to move to an island 3182 km away and come back. How much time will it take for the entire journey if the speed of the stream is 1.5 km/hr.?

  1. 300 hours

  2. 350 hours

  3. 375 hours

  4. 320 hours

  5. 250 hours
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Downstream speed (with current) = 20+1.5 = 21.5 km/hr. Upstream speed (against current) = 20-1.5 = 18.5 km/hr. Time for each leg of 3182 km: downstream = 3182/21.5 = 148 hours, upstream = 3182/18.5 = 172 hours. Total time = 148+172 = 320 hours. Options A (300), B (350), C (375), and E (250) are incorrect.

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