Question

If the length and height of a brick increases by 10% each respectively, and the breadth reduces by 20%, what is the percentage change in the volume of the brick?

Options

• 2.8

• 3.0

• 3.2

• 3.6

Answer 1

3.2

Explanation:

Let initial volume of brick = 100

After increase in length and height be 10%

and reduction in breadth by 20%

New volume,

V = `100 [1 + 10/100][1 + 10/100][1 - 20/100]`

`= 100 (11/10)(11/10)(8/10) = 96.8%`

Reduction = 100 - 96.8 % = 3.2 %