A boat moves at 15 km/h in still water. The river current is 3 km/h. How long will it take to travel 36 km downstream?
Correct answer: A. 2 hours
Downstream, the current adds to the boat's speed: 15 + 3 = 18 km/h. Time = 36 ÷ 18 = 2 hours. Upstream, the speed would be 15 − 3 = 12 km/h, taking 3 hours.
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