Sometimes it is necessary to reverse percentage problems. For example, if the price of a television set includes VAT, you might need to know how much of the price is the VAT.
Worked Examples
The price of a computer is £1398, including VAT at 16%. Find the actual cost of the computer and the amount of VAT which has to be paid.
To add 16.5% VAT to a price it should be multiplied by 1.165. So to remove the VAT the price should be divided by 1.165.
| Original Price | = |
| = £1200 | |
| VAT | = £1398 − £1200 |
| = £198 |
A customer is offered a 20% discount when buying a new bed. The discounted price is £158.40. Find the full price of the bed.
To find the discounted price of the bed, the full price should be multiplied by 0.8. So to find the full price, the discounted price should be divided by 0.8.
| Full price | = |
| = £198 |
Sharon invests some money in a building society at 6% interest per annum. After two years the value of her investment is £28 090. Find the amount she invested.
To find the final value, the amount invested would be multiplied by 1.062. To find the amount invested, divide the final value by 1.062.
| Amount invested | = |
| = £25 000 |
Exercises
