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SSC Selection Post 2022 PYQ — Question 61

SSC Selection Post - Graduation Level 2022 - 10 Feb 2022 - Shift 3 • Quantitative Aptitude • Q61

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If x + y = 565\over6, and 1x1\over{x}+ 1y1\over{y}= 7121\over2, then what is the value of x3 + y3?

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 6521665\over216.

1/x + 1/y = (x + y)/xy = 15/2

⇒ (5/6)/xy = 15/2

⇒ xy = 1/9

So, x3 + y3 = (x + y)3 - 3xy(x + y)

= (5/6)3 - 3 × (1/9) × (5/6)

= 125/216 - 15/54

= 65/216