He needs to score 86 in fourth test to have an average of 80.
Step-by-step explanation:
Given scores are;
76, 81 and 77
Average = 80
Let x be the fourth test score.
As we know;
[tex]Average =\frac{Sum\ of\ the\ terms}{Number\ of\ terms}\\80=\frac{76+81+77+x}{4}[/tex]
Multiplying both sides by 4
[tex]4*\frac{76+81+77+x}{4} = 80*4\\76+81+77+x = 320\\234+x=320\\x=320-234\\x=86[/tex]
He needs to score 86 in fourth test to have an average of 80.
Keywords: Average, Addition
Learn more about addition at:
- brainly.com/question/7888686
- brainly.com/question/8224301
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