After every ninth visit to a restaurant you receive a free beverage. After every twelfth visit you receive a free appetizer. if you visit the restaurant 100 times, on witch visits will you receive a free beverage and a free appetizer? At which visit will you first receive a free beverage and a free appetizer

A common multiples problem.

Multiples of 9 till 100:

9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99

Multiples of 12 till 100:

12, 24, 36, 48, 60, 72, 84, 96

Look for the common ones in 9 and 12:

36 and 72

So, on the 36th and the 72nd visit you'll get an appetizer and drink.

So, on the 36th visit is the first time you'll get a free appetizer and drink.