SSC CHSL 2021 PYQ — Question 71

The correct answer is option 3 i.e. 140

As we know the formula

(X + Y)³ = (X + Y) (X² + Y² - XY) ............1

According to the question

(0.8 x 0.8 x 0.8 + 0.6 x 0.6 × 0.6) / (0.08 x 0.08 + 0.06 x 0.06 -  0.08 x 0.06)

= (0.8³ × 0.6³) / { 0.01 * (0.8 x 0.8 + 0.6 x 0.6 -  0.8 x 0.6)}

=  (0.8 + 0.6) * (0.8 x 0.8 + 0.6 x 0.6 -  0.8 x 0.6) / { 0.01 * (0.8 x 0.8 + 0.6 x 0.6 -  0.8 x 0.6)}

=(0.8 + 0.6) * 100

= 140