Speed Time & Distance Question Answers

Speed, Time and Distance - Quant/Math - CAT 2008

Question 4 the day: November 17, 2003

The question for the day is from the topic of Speed, Time and Distance.

A man can row 50 km upstream and 72 km downstream in 9 hours. He can also row 70 km upstream and 90 km downstream in 12 hours. Find the rate of current.

(1)	3 km/hr			(2)	8km/hr
(3)	4 km/hr			(4)	None of these

Correct Answer - (3)

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Solution:


Let x and y be the upstream and downstream speed respectively.

Hence 50/x + 72/y = 9 and 70/x + 90/y = 12

Solving for x and y we get x = 10 km/hr and y = 18 km/hr

We know that Speed of the stream = 1/2 * (downstream speed - upstream speed) = 1/2 (18 � 10) = 4 km/hr.