Question

Swimming pools must have a certain amount of chlorine content. The United States standard for safe levels of chlorine in swimming pools is at least 1 part per million and no greater than 3 parts per million. Write a compound

inequality for the acceptable range of chlorine levels.

Answer 1

1 ≤ c ≤ 3

Explanation:

In order to meet the standard, the chlorine level (c) must be at least 1 part per million (equal to or greater than 1):

1 ≤ c

At the same time, the level also needs to be no greater than 3 parts per million (equal to or lesser than 3)

c ≤ 3

Combining both inequalities yields (in parts per million):

1 ≤ c ≤ 3.

The compound inequality above describes the acceptable range for chlorine levels.