so sale price= normal price-dicount
sale price=100%-20%=80%
therfor
220=80%of origonal price
80%
percent means parts out of 100
80%=80/100=8/10
220=8/10of origonal price
multiply both sdies by 10
2200=8 of origoal price
divide by 8
2200/8=275
origonal price=275