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Question:

Rick scored 85, 88, 62, and 79 on his previous exams. What is the minimum score he must earn on his next exam to have an overall average of at least 80?

A 86
Explaination

The average of a set of numbers is the sum of the numbers in the set divided by the number of numbers in the set. Use x to represent the last test, and set up the inequality for the average. An inequality is necessary because the question asks for the smallest number that will yield an average larger than 80, not greater than or equal to 80: $4945_w214_h38.png$ which becomes 85 + 88 + 62 + 79 + x \u2265 400 or 314 + x \u2265 400, or x \u2265 86