The chlorine in the water of a swimming pool is considered normal if if the average of three chlorine readings between 7.2 and 7.8. The first two readings are 7.4 and 7.9

This is the inequality that models the above situation
(7.4 + 7.9 + C)
7.2 ≤ ≤ 7.8
3

Find the possible values of the third reading, C that will make the average chlorine.

Create an inequality that can be used to find the range for the third chlorine reading , then solve it .