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SSC CHSL 2021 PYQ — Question 67

SSC CHSL - 13 April 2021 - Shift 3 • Quantitative Aptitude • Q67

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If k - 3k=5\frac{3}{k}=5, then what is the value of k2 + 9k2\frac{9}{k^2}?

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 31

k-3k=5\frac{3}{k}=5

Squaring both sides: 

(k−3kk-\frac{3}{k})2=5 2

k2+9k2−2×k×3kk^2 +\frac{9}{k^2} -2×k ×\frac{3}{k} = 25

k2+9k2k^2 +\frac{9}{k^2}= 31