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SSC CGL 2017 PYQ — Question 72

SSC CGL Tier II Quant - 12/01/2017 • Quantitative Aptitude • Q72

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If a = 1/(a - 5) (a > 0), then the value of (a + 1/a) is:

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Correct answer: A

Explanation

The correct answer is Option 1 i.e. √29

Application

a = 1/(a – 5)

⇒ a2 – 5a = 1

Divide by a:

⇒ a – 5 = 1/a

⇒ a – 1/a = 5

Taking square:

⇒ a2 + 1/a2 – 2 = 25

⇒ a2 + 1/a2 = 27

⇒ a + 1/a = √(27 + 2) = √29