Mathematics
nguyenpatrick23
22

On his first two social studies tests, Billy made an 86 and a 93. What grade must Billy make on the third test to have an average of 90 for all three tests? a. 91 c. 85 b. 87 d. 90

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(1) Answers
Audge

We know that there are 3 tests and he's already taken 2. The definition of average it to add up all the scores and divide by how many tests there are. setup: [latex] \frac{86 + 93 + n}{3} = 90 [/latex] multiply each side by 3 : 86 + 93 + n = 270 Simplify: 179 + n = 270 Subtract 179 from each side: n = 91 so A

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