Using multipliers is a more efficient method for calculating a percentage increase or decrease. It involves finding a number you can multiply by that represents the percentage change.
What multiplier would represent an increase of 29%?
An increase of 29% would result in a value of 100% + 29% = 129%
As a fraction this would be written as \(\frac {129} {100}\).
This is the same as 1.29.
So multiplying by 1.29 is the same as increasing a value by 29%.
Question
Suzie’s investment of £200 increases by 3%. Using multipliers, what is her investment now worth?
£206
100% + 3% = 103.
103 ÷ 100 = 1.03 is the multiplier.
£200 × 1.03 = £206
What multiplier would represent a decrease of 7.3%?
A decrease of 7.3% would result in a value of 100% - 7.3% = 92.7%
As a fraction this would be written as \(\frac {92.7} {100}\).
This is the same as 0.927
Therefore, multiplying by 0.927 is the same as decreasing a value by 7.3%.
Question
Adele goes travelling with £1,500 and spends 65% of her savings. Using multipliers, calculate how much money she has at the end.
