A waiter at 'The Greasy Spoon' restaurant had twenty-six customers to wait on. During the lunch rush he added another twenty customers. If twenty-nine of the customers didn't leave him a tip, how many customers did leave a tip?

Answer 1

The total number of customers the waiter had to wait on was 26 + 20 = 46.
If 29 customers didn't leave a tip, then the number of customers who did leave a tip is 46 - 29 = 17.
Therefore, 17 customers left a tip.