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#