On two examinations, you have grades of 89 and 84. There is an optional final examination, which counts as one grade. You decide to take the final in order to get a course grade of A, meaning a final average of at least 90. What must you get on the final to earn an A in the course?

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Mathematics

16 September, 00:17

On two examinations, you have grades of 89 and 84. There is an optional final examination, which counts as one grade. You decide to take the final in order to get a course grade of A, meaning a final average of at least 90. What must you get on the final to earn an A in the course?

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Answers (2)

Know the Answer?

Quinton Garrison · Answer 1

Atleast 97

Step-by-step explanation:

(89 + 84 + X) / 3"90

173 + X"270

X"270 - 173

X"97

Rachael Mayer · Answer 2

Answer: The grade must be greater than or equal to 97

Step-by-step explanation:

This is a question about averages. One determines averages by adding up all the original numbers (89 and 84) and dividing by the number of numbers (2). If we want to find out a third test grade that would get the grade up to a 90 we should use the formula for finding averages as an algebraic equation.

Set up the equation

89 + 84 + x/3 = 90

The x represents the third test grade, which is what we must solve for. The 89 and 84 were the two previous grades. And the 90 is what the average must be according to the question.

Solve the equation.

1. 89 + 84 + x/3 = 90

2. 89 + 84 + x = 270

3. 84 + x = 181

4. x = 97