If (64)² - (36)² = 20 × x, then x = ?

A. 70

B. 120

C. 180

D. 140

E. None of these

Answer: Option D

Solution(By Examveda Team)

$$\eqalign{ & 20 \times x = \left( {64 + 36} \right)\left( {64 - 36} \right) \cr & 20 \times x = 100 \times 28 \cr & \therefore {\kern 1pt} x = \frac{{100 \times 28}}{{20}} \cr & \,\,\,\,\,\,\,\,\,\,\, = 140 \cr} $$