Interview Q&A / Aptitude
Aptitude interview questions
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- A boat's speed in still water is 15 km/h. It goes 30 km upstream and returns in 4 hours 30 minutes. What is the speed of the stream?
5 km/h. Solve 30/(15 - s) + 30/(15 + s) = 4.5. This gives 900/(225 - s^2) = 4.5, so 225 - s^2 = 200 and s = 5. Check: 30/10 + 30/20 = 3 + 1.5 = 4.5 hours.
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