Question

How do you increase £80 by 20%?

Answer 1

I have shown 3 approaches

`£96`

Explanation:

The % sign is a unit of measurement and it is worth `1/100`

so 20% `-> 20xx1/100 = 20/100`

so 20% of £80 is:`" "20/100xx£80 = £16.00`

As this is increase we have `£80+£16 = £96`

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`color(blue)("Or you can also do it like this:")`

`20/100 -=(20-:20)/(100-:20) = 1/5`

so 20% of £80 is:`" "1/5xx£80 = £16.00` and the rest as above.

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`color(blue)("Or you can also do it like this:")`

`£80(1+1/5) = £80+£16=£96`