How do you increase £80 by 20%?

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Answer 1 · 2016-11-24T11:46:26

I have shown 3 approaches

$£96$

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

$£80(1+1/5) = £80+£16=£96$