First you have to find 25% of $28.80 (which is 7.20). Then, you subtract the $7.20 from your 28.80. You do that because you are getting a 25% discount. Then, you find 10% of $21.60 (your answer for the 25% discount) and you subtract 10% of $21.60. After that, you get your total of $19.44.
