Quantitative Aptitude • Time, Speed & WorkMedium
A boat moves at 4 km/h in still water and the stream flows at 1 km/h. How long will the boat take to go 30 km downstream and come back?
A. 16 hours✓ Correct Answer
B. 10 hours
C. 15 hours
D. 6 hours
💡 Solution & Explanation
Downstream the stream helps: 4 + 1 = 5 km/h, so going takes 30 ÷ 5 = 6 hours. Upstream the stream works against it: 4 − 1 = 3 km/h, so coming back takes 30 ÷ 3 = 10 hours. Total time = 16 hours.
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