Okay, to work out the original price, all you have to do is get the sale price ($146.54) and then divide it by 1 - 0.[whatever the percentage is]. In this case, the percentage is 15%, so you do 1 - 0.15 = 0.85.
So to work out the original price, you do:
146.54 ÷ 0.85 = $172.40
The original price is $172.40. :)