Question

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

• A. 50
• B. 125
• C. 750
• D. 300

Answer 1

The correct option is B 125

Suppose each edge of a cube is 100 cm. After increase by 50% the edge = 150 cm Surface area of the cube before increase
$=6\times 100\times 100$
$=60000c{m}^2$
and surface area of the cube after increase
$=6\times 150\times 150$
$=135000c{m}^2$
$\therefore$ Increase in the surface
$=135000-60000$
$=75000c{m}^2$
Hence per cent of increase in the surface
$=\frac{75000\times 100}{60000}=125$