SarkariPYQ

SSC CGL 2022 PYQ — Question 69

SSC CGL - 21 April 2022 - Shift 3 • Quantitative Aptitude • Q69

Back to paper

If (a + 1a+32\frac{1}{a}+3^2) = 16, where a is a non-zero real number, then find the value of a2 + 1a2\frac{1}{a^2}.

Show answer & explanation

Correct answer: C

Explanation

 The correct answer is option 3 i.e. 47.

⇒ (a + 1a+32\frac{1}{a}+3^2) = 16

⇒ (a + 1a+32\frac{1}{a}+3^2) = 16

⇒ a + 1/a = 16 - 9

⇒ a + 1/a = 7

⇒ (a + 1/a)2 = 72

⇒ a2 + 1/a2 + 2 = 49

⇒ a2 + 1/a2 = 47