well, let's take a looksie at what it would have been had there not been a sale, so at regular price the washer and dryer are just 685.96 + 475.70 = 1161.66, well hell how much is 4.25% of that?

now, since we know the appliances are going to be 20%, that means the appliaces sale price will be 100% - 20% = 80%, so 80% of the original price, well, we know the original price for those two is 1161.66, what's 80% of that?

well, Paula could have made 49.37, but she ended up with 39.5, 49.37 - 39.5 ≈ 9.87.