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SSC Selection Post 2022 PYQ — Question 57

SSC Selection Post - Higher Secondary Level 2022 - 16 March 2022 - Shift 3 • Quantitative Aptitude • Q57

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The time taken by a boat to travel  a certain distance downstream is 35{{3} \over 5} of the time taken by it to travel the same distance upstream. The speed of the stream is 4 km/h. How much time (in hours) will it take to travel 18 km downstream and 15 km upstream?

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 2.15.

Let the speed of boat in still water be x.

Given, 5(x - y) = 3(x + y)

⇒ 5x - 5y = 3x + 3y

⇒ 2x = 8(4)

⇒ x = 16

Required time = 1816+4+1516−4\frac{18}{16 + 4} + \frac{15}{16 - 4} 

⇒ 18/20 + 5/4 

⇒ 43/20 = 2.15 h