The Relationship between Fractions and Percentages
Exercises - Percentage Increases and Decreases
Percentage Increases and Decreases
In order to apply a percentage increase or decrease to a number, simply calculate the percentage of the number you are trying to work out and then add or subtract the answer from the original figure.
Examples
In a sale, the price of a coat is reduced by 25% from £80. What is the new price?
£80 ÷ 100 = £0.80
£.0.80 x 25 = £20
£80 - £20 = £60
In the budget, tax on cigarettes increases by 5%. If the price of 20 cigarettes in £3.20, what will it be after the 5% increase?
£3.20 ÷ 100 = 0.032
£0.032 x 5 = 0.160 (16p)
£3.20 + 0.16 = £3.36
20 cigarettes will cost £3.36 after the 5% increase.
How do I show these increases/decreases as fractions?
Look at the percentage increase/decrease figure and calculate how many times the figure will go into 100.
100 ÷ 25 = 4 – So the price of the coat has fallen by 1/4.
100 ÷ 5 = 20 – So the price of cigarettes has risen by 1/20.
If you are working out fractions from percentage figures, make sure that your answer becomes the denominator on the fraction (the bottom number). For more information on the relationship between percentages and fractions, click on the link at the top of the screen.