Subject
Quantitative Aptitude
Topic
Speed & Distance
A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
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10Explanation
Let the speed of the stream be x km/hr then, Speed downstream = (15+x) km/hr, Speed upstream = (15 - x) km/hr. So, 30/(15+x)+30/(15-x) = 4(2/1) => 900/(225-x2) = 9/2 => 9x2 = 225 => x2 = 25 => x = 5 km/hr.Related questions
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