Question

If each edge of a cube is increased by 50%, then the percentage increase in the surface area is

• A. 50
• B. 125
• C. 150
• D. 300

Answer 1

Answer: (B)

125

Let the original side be $a$ then

Original surface area $S=6a^2$

When side is increased by $50\%$, side becomes $\frac{3}{2}a$ then

Surface area $s=\frac{27}{2}{a}^2$

Hence,

Surface area is increases by $x=\frac{\frac{27}{2}{a}^2-6a^2}{6a^2}\times 100=125\%$

This is the required solution.