### Home > CCG > Chapter Ch10 > Lesson 10.3.2 > Problem 10-129

10-129.

An engineer is designing the operator panel for a water treatment plant. The operator will be able to see four LED lights in a row that indicate the condition of the water treatment system. LEDs can be red, yellow, green, or off. How many different conditions can be signaled with the LEDs?

Use a decision chart. See the Math Notes box in Lesson 10.3.1 for an example.