Lisa purchased a concert ticket on a web site. The original price of the ticket was $75. She used a coupon code to received a 20% discount. The web site applied a 10% service fee to the discount price. Lisa's ticket was less than the original price by what percent?

12%

Step-by-step explanation:

Her discounted price was 100% - 20% = 80% of the original price. The service fee made it be 100% + 10% = 110% of that, so her final price was ...

... 110% * 80% = 88%

of the original ticket price.

This represents a discount of 100% - 88% = 12% from the original.