# Example 3

- Author:
- Walch Education

- 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 using variables to represent the amount of time needed to make the rulers.
- Use the same variables to write an inequality to represent the amount of time needed to paint the rulers.
- Determine the constraints on this situation, then write inequalities to represent these constraints.
- To write the system of inequalities for this situation, combine all the inequalities related to the situation and list them in a brace, {.