# CCSS IP Math I 1.4.1 Example 3

- Topic:
- Inequalities

A school supply company produces wooden rulers and plastic rulers. The rulers must first be made, and then painted.

- It takes 20 minutes to make a wooden ruler. It takes 15 minutes to make a plastic ruler. There is a maximum amount of 480 minutes per day set aside for making rulers.
- It takes 5 minutes to paint a wooden ruler. It takes 2 minutes to paint a plastic ruler. There is a maximum amount of 180 minutes per day set aside for painting rulers.

- Identify the information you know.
- Write an inequality to represent the amount of time needed to make the rulers. Let
*w*represent the wooden rulers and*p*represent the plastic rulers. - Write an inequality to represent the amount of time needed to paint the rulers. Use the same variables to represent wooden and plastic rulers.
- Now consider the constraints on this situation. It is not possible to produce a negative amount of either wooden rulers or plastic rulers; therefore, you need to limit the values of
*w*and*p*to values that are greater than or equal to 0. - Combine all the inequalities related to the situation and list them in a brace, {. These are the constraints of your scenario.