The price of a camera is increased by 30%. Later in a sale, the new price is reduced by 20%. What percentage change is the sale price compared to the original price? (It's not 10%!)
50%
if you work on the basis that the camera was originally £90
it is reduced by 30% so now costs £60
it is reduced by a further 20%
so take £15 off £60 so it is now only £45
which is half of £90
To increase a price by 30% multiply the amount by [100% + 30% = 130%] 1.30
to then reduce a price by 20% multiply the amount by [100% - 20% = 80%] 0.80
x 1.3 then x 0.8 is equivalent to x 1.04 [13 x 8 = 104 so 1.3 x 0.8 = 1.04]
1.04 = 104% so overall price increase is 4%.