1. Children must be at most 36 inches tall to ride the kiddie roller
coaster. Let h = the height required to ride the kiddie roller coaster.

2. The gym can seat a maximum of 1200 people.
Let n = the number of people who can sit in the gym.

3. Children must be at least 13 to go to a PG-13 rated movie.
Let a = the age you must be to attend a PG-13 movie.