Brush up your maths: answer to percentage increase and decrease exercise

How much would a plumber's bill for 452 before tax be after 17½% VAT was added? How much would a restaurant bill for 62.50 be after a 10% loyalty card bonus was subtracted?

A plumber's bill for 452 plus 17½% VAT would be 531.10. To add 17½% we first convert to 0.175. We now add this to 1.00 to give 1.175. We now multiply 452 × 1.175 = 531.1

A restaurant bill for 62.50 be after a 10% loyalty card bonus was subtracted would be 56.25. To subtract 10% we convert 10% to 0.10. We subtract from 1.00 to give 0.90. We multiply 62.50 × 0.90 = 56.25. (Then you leave the 10% as a tip.)


Back to question.

To Martin Bland's M.Sc. index.

To Martin Bland's home page.

This page maintained by Martin Bland.
Last updated: 3 October, 2007.

Back to top.