SOLUTION:
Step 1:
In this question, we are given the following:
Given that every tenth person in line will get a coupon for a free box of popcorn at the movies.
We are meant to find the probability that you don't get a coupon when you are in the line.
Step 2:
We can see that the probability that the person was in the line and got a coupon is:
[tex]\frac{1}{10}[/tex]
Then, the probability that the person did not get a coupon when he was in the line is:
[tex](\text{ 1 -}\frac{1}{10})\text{ = }\frac{9}{10}[/tex]
