Hello! So the first thing you want to do to solve this question is to add up the cost of both the carrier and the cat tower. Once you have the sum, the next step would take the 5% discount and add it to the 15% discount. Next, take the sum of the cat items and plug them into the correct formula with the sum of the discounts. The formula would be saying the sum of the percents (in decimal form) of (which in math means multiply) whatever your previous sum was concerning the cats. Your product of this equation would be the discount that Andrea was receiving, and you would subtract that from your original product pertaining to cat objects. That would be your final answer. Then, you just compare. If you have any other questions on how this is solved, just message me back. Hope this helped!