Ok so 30% as a decimal would be .3 so you have to multiply .3 by 315 and you will get 94.5 wich is how much is discounted off. so now subract 94.5 from 315 and that is 220.50 and that is the price hope this helps
The original price was 409.5 because 30% of 315 equals 94.5 so that was what they subtracted from 315 so to know the original price you add 94.5 to 315 and the answer is 409.5
