Answer: Hello there!
As we know, the dress pants cost a total of $40, and we also know that Skylar has a coupon of y percent in the dress pants and a coupon of z percent in the total purchase.
In this problem, the question is:
Skylar uses the dress pants coupon. Which part of the expression represents the percent that Skylar will pay for the dress pants?
Ok, if we have a discount of y percent, (where y is represented as decimals) means that you are paying the total price of something ( the 100%) minus the the decimal y multiplied by the price of the object.
this is: $40 - y*$40 = (1 - y)*$40
then if the dress pants cost $40, and Skylar only uses the dress pants coupon, he will pay (1 - y)*$40 for the dress pants.