Eric bought lunch for him and his friends at Papa's Pizza. His bill was $50 with tax. If he used a 15% off coupon and then left a 20% tip based on the discounted ticket, how much did he have left out of $100 bill?
The initial cost of Eric's bill before the discount was $50. With a 15% discount, he saved 15/100 * $50 = $7.50. Therefore, his discounted bill was $50 - $7.50 = $42.50.
Then, he left a 20% tip on the discounted bill which is 20/100 * $42.50 = $8.50.
Therefore, his total cost including tax and tip was $42.50 + $8.50 = $51.
Eric had $100 to begin with, so the amount he had left was $100 - $51 = $49.