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SSC CGL 2021 PYQ — Question 59

SSC CGL - 17 Aug 2021 - Shift 1 • Quantitative Aptitude • Q59

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A takes 8 hours more than the time taken by B to cover a distance of 160 km. If A doubles his speed, he takes 3 hours more than B to cover the same distance. the speed (in km/h) of B is:

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Correct answer: D

Explanation

The correct answer is Option 4 i.e. 80​​​​​​.

Let the speed of A and B be a' km/hr and 'b' km/hr.

According to the question,

160a−160b=8\frac{160}{a}-\frac{160}{b} = 8..............(1)

If A doubles his speed then it takes 3 hours more than B.

1602a−160b=3\frac{160}{2a}-\frac{160}{b} = 3.............(2)

Subtract equation (2) from equation (1) we get,

160a−80a=5\frac{160}{a}-\frac{80}{a}=5

⇒ a = 16km/hr.

Put the value of a in equation 1 we get b = 80 km/hr.