Charlie is hoping to earn an A (90%) average on his tests, but also wants to earn at least a B (80%). His first three test scores are 80, 85, 95. What is the lowest score he can earn on the fourth test and still earn a B? What score must he earn on the fourth test to earn an A?
1. Write a compound inequality that can be used to solve the problem.
2. Solve the compound inequality. Show steps.
3. Answer the questions with a sentence in context of the problem.