To find out what score the student needs on the fifth quiz to have an average of at least 85, we can use the formula for average:
Average = Sum of Scores / Number
of Scores
The student has taken four quizzes and has scores of 88, 80, 95, and 76. To calculate the sum of these scores, we add them together:
Sum of Scores = 88 + 80 + 95 + 76 = 339
Since we have four scores, the number of scores is 4.
Now, let's denote the score on the fifth quiz as x. We want to find the value of x that will give us an average of at least 85.
We can set up an equation:
(339 + ×) / 5 ≥ 85
To solve for x, we can multiply both sides of the inequality by 5:
339 + ×≥ 85 * 5
339 + ×≥ 425
Subtracting 339 from both sides of the inequality gives us:
× ≥ 425 - 339
× ≥ 86
Therefore, the student must score at least 86 on the fifth quiz to have an average of at least 85.