Question

Each edge of a cube is increased by 50% The percentage increase in the surface area of the cube is

• A. $50$
• B. $125$
• C. $150$
• D. $225$

Answer 1

The correct option is B $125$

Let the edge of cube be 'a' unit

Surface area of cube$=6a^2$

Increase edge$=a+50$ % of $a=\frac{3a}{2}$

New surface area$=6\times {\left(\frac{3a}{2}\right)}^2=13.5a^2$

% increase in area$=\frac{13.5a^2-6a^2}{6a^2}\times 100$

$=\frac{7.5}{6}\times 100=125$%