Question

9) Gabriel took three math tests last semester. He scored a 91 on the first test, a

72 on the second test, and he couldn't remember what he scored on the third
test. When he saw his progress report, he saw that the average score for his
three tests was an 80. What did Carlos score on his third test?


PLEASE ANSWER ASAP I GOT UNTIL 6:30 AND I DONT GET IT

Answer 1

The average of anything can be calculated by adding up all the terms and dividing by the number of terms.

In this case,

the number of terms = 3

x = the missing test score.

(91 + 72 + x) / 3 = 80

Let's multiply both sides by 3

91 + 72 + x = 240

Combine like terms.

163 + x = 240

Subtract 163 from both sides

x = 77

Carlos scored a 77 on his third test.