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SSC Selection Post 2019 PYQ — Question 61

SSC Selection Post - Graduation Level 2019 - 16 Oct 2019 • Quantitative Aptitude • Q61

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A and B start moving from a place X to Y and Y to X, respectively, at the same time on the same day. After crossing each other, they complete their remaining journeys in 549\frac{4}{9} hours and x hours, respectively. If the ratio of the speeds (in km/h) of A and B is 9: 7, then what is the value of x?

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Correct answer: B

Explanation

The correct answer is Option 2 i.e. 9.

A takes 49/9​ hrs after meeting

Speed ratio A : B = 9 : 7

vAvB=tBtA\quad \frac{v_A}{v_B} = \sqrt{\frac{t_B}{t_A}} \\

97=x49/9⇒(97)2=x49/98149=x49/9⇒x=8149×499=9\frac{9}{7} = \sqrt{\frac{x}{49/9}} \Rightarrow \left( \frac{9}{7} \right)^2 = \frac{x}{49/9} \\ \frac{81}{49} = \frac{x}{49/9} \Rightarrow x = \frac{81}{49} \times \frac{49}{9} = 9