## Chain or Compound Percentages

If £50 is increased by 10%, we calculate 10% of £50 and add the answer.

£50+£5=£55

We could have obtained the same answer by multiplying £50 by

$1+10\%=1+\frac{10}{100}=1.1$

This method is especially convenient when an amount is increased several times by different percentages.

Suppose £50 is increased in turn by 10%, 15%, 20% and 25% successively.

To increase by 10% multiply by &nbsp;

$1+10\%=1+\frac{10}{100}=1.1$

To increase by 15% multiply by &nbsp;

$1+15\%=1+\frac{15}{100}=1.15$

To increase by 20% multiply by &nbsp;

$1+20\%=1+\frac{10}{100}=1.2$

To increase by 25% multiply by &nbsp;

$1+25\%=1+\frac{10}{100}=1.25$

To increase by 10% then 15% then 20% then 25%, multiply by