SSC Selection Post 2019 PYQ — Question 61

The correct answer is option 2 i.e. 10.

a³ - b³ = (a - b)(a² + ab + b²)

Given, ${0.49+0.7 \times 0.8 + 0.64 \over 0.512 - 0.343}$

This is in the form of ${a^2+a \times b + b^2 \over a^3 - b^3}$.

⇒ ${(0.7)^2+0.7 \times 0.8 + (0.8)^2 \over 0.8^3 - 0.7^3}$ 

⇒  ${1 \over0.8 - 0.7}$ = 10