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SSC CGL 2021 PYQ — Question 67

SSC CGL - 20 Aug 2021 - Shift 1 • Quantitative Aptitude • Q67

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If (2a+3a−1)=11(2a + \frac{3}{a}-1)=11, what is the value of (4a2+9a2)?(4a^2 + \frac{9}{a^2})?

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 132.

2a + 3/a = 11 + 1

2a + 3/a = 12

On sqaring both sides

⇒ 4a2 + 9/a2 + 2 × 2a × 3/a = 144

⇒ (4a2+9a2)(4a^2 + \frac{9}{a^2}) = 144 - 12 = 132