Practice!

Sample Problem

The length and breadth of a box is increased by 18% and 15% respectively and the height of it is decreased by 20%. Calculate the percentage change in the volume of the box. (Round to the nearest hundredth.) %

Solution

Assume the original length, breadth and height are respectively x, y and z.

Length: x × (1 + 18%) = 1.18 x

Breadth: y × (1 + 15%) = 1.15 y

Height: z × (1- 20%) = 0.8 z

Thus, the percentage change in the volume: (1.18 x × 1.15 y × 0.8 z – xyz) / xyz = 8.56%