Answer:
Your answer would be the 60th
Step-by-step explanation:
This is your solution due to the fact that when you find the multiples of 12 and 30 you will realize that that's the first number they meet at, let me show you.
Multiples of 12 - 12, 24, 36, 48, 60
Multiples of 30 - 30, 60, 90, 120, 150
So The Least Common Denominator is 60!
Thus that is how I know that the 60th customer at the movie theater would get both items for free.
Hope This Helped!