Multiple choice

Joe and his family went on a boat trip to an island, which was 20 km away from their current location, and it took them 5 hours to reach there while travelling in the upstream direction. While travelling back to the same location downstream, it took them 2 hours. What would be the speed of the boat in still water?

  1. 7 kmph

  2. 6 kmph

  3. 5 kmph

  4. 4 kmph

  5. 3 kmph
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A Correct answer
Explanation

Upstream speed = 20/5 = 4 km/hr. Downstream speed = 20/2 = 10 km/hr. Boat speed = (Downstream + Upstream) / 2 = (10 + 4) / 2 = 7 km/hr.

AI explanation

The upstream speed is 20 km divided by 5 hours, which equals 4 kmph. The downstream speed is 20 km divided by 2 hours, which equals 10 kmph. The speed of the boat in still water is the average of upstream and downstream speeds, calculated as (4 + 10) / 2. This results in a still water speed of 7 kmph.

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