Question

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

विकल्प

• 50%

• 75%

• 100%

• 125%

Answer 1

 125%
Let the original edge of the cube be a units.
Then, the original surface area of the cube = 6a² units

New edge of the cube = 150% of a 

`= (150"a")/100`

`= (3"a")/2`

Hence, new surface area `= 6  × ((3"a")/2)^2`

`=(27a^2)/2`

Increase in area` =((27a^2)/2 - 6"a"^2) `

                         `=(15"a"^2)/2`

% increasein surface area `= ("15a"^2/2xx1/(6"a"^2xx100))%`

=125 %