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SSC CGL 2023 PYQ — Question 29

SSC CGL Tier II - 7 March 2023 - Shift 1 • Quantitative Aptitude • Q29

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The value of 0.7×0.7×0.7+0.3×0.3×0.30.7×0.7−0.7×0.3+0.3×0.3{0.7 \times0.7 \times0.7+0.3 \times0.3 \times0.3}\over{0.7 \times0.7 -0.7\times0.3 +0.3 \times0.3} is _______

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Correct answer: B

Explanation

The correct answer is Option 2 i.e. 1

= 0.7×0.7×0.7+0.3×0.3×0.30.7×0.7−0.7×0.3+0.3×0.3{0.7 \times0.7 \times0.7+0.3 \times0.3 \times0.3}\over{0.7 \times0.7 -0.7\times0.3 +0.3 \times0.3}

Formula used

a3 + b3 = (a2 – ab + b2)(a + b)

put a = 0.7 and b = 0.3

0.7 × 0.7 × 0.7 + 0.3 × 0.3 × 0.3 = (0.7× 0.7 - 0.7 × 0.3 + 0.3 × 0.3) (0.7 + 0.3)

(0.7 × 0.7 × 0.7 + 0.3 × 0.3 × 0.3)/(0.7× 0.7 - 0.7 × 0.3 + 0.3 × 0.3) = (0.7 + 0.3) = 1