Question

The library needs at least 15 people to sign up for an event in order to run it. Currently, 3 people have signed up, and the library expects 2 more people to sign up each day. After how many days will the library be sure it can run the event? Write an inequality that could be used to solve this problem.

Answer 1

Let d = number of days. The inequality is

3 + 2d ≥ 15.

Solve: 2d ≥ 12, so d ≥ 6.

So after 6 days the library will be sure it can run the event (they will have at least 15 people).