The percentage increase in the surface area of a cube when each side is doubled is :

A. 200%

B. 300%

C. 150%

D. 50%

Answer: Option B

Solution(By Examveda Team)

We know that
⇒ Total surface area of a cube
⇒ 6a²
⇒ If each side is doubled i.e. 2a
⇒ Total surface area of a cube
⇒ 6 × (2a)²
⇒ 24a²
Increase in surface area = 24a² - 6a² = 18a²
∴ % Surface area of cube will increase :
$$\frac{{18{a^2}}}{{6{a^2}}} \times 100 $$
= 300%