Competititve Exams Materials
(Q) While talking about a place to his friend Prashant said, "I could swim downstream to the place in 12 hours but while coming upstream it took 18 hours. The river was running at a speed of 6 km/hr." What is his speed in still water?
A) 30 km/hr
B) 28 km/hr
C) 35 km/hr
D) 44 km/hr
Explanation :
Man's/Boat's Speed = X
Stream/Current/River Speed = Y
∴ Downstream speed = X + Y
Upstream speed = X - Y
∴ X+Y = (X+6) km/hr and X-Y = (X-6) km/hr
Distance is same
∴ D=D
∴ (X+6) x 12 = (X-6) x 18
∴ X=30 km/hr = Speed of Prashant
B) 28 km/hr
C) 35 km/hr
D) 44 km/hr
View Answer
A) 30 km/hrExplanation :
Man's/Boat's Speed = X
Stream/Current/River Speed = Y
∴ Downstream speed = X + Y
Upstream speed = X - Y
∴ X+Y = (X+6) km/hr and X-Y = (X-6) km/hr
Distance is same
∴ D=D
∴ (X+6) x 12 = (X-6) x 18
∴ X=30 km/hr = Speed of Prashant
View related categories
Aptitude : Boats and Streams
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