Verified answer

x(1-20%)=100

x=125

It can be solved using proportion.

Original price = 100%

20% off = 100% - 20% = 80%

Therefore, $100 = 80% of the original price.

Through proportion: $100:80% = original price:100% use decimal instead of percent and use X for original price

0.80X = 100(1)

Divide both sides by 0.80 (or 80%) and you will get $125

Sorry I don't know how to type that character of currency so I used a dollar sign instead. :)

On a 20% off special offer, a shirt is £100

100 is 80% of the original price

80%=0.8

100/0.8

125

£100(100/80) = £125 ...............Ans