Question

question 4 molly has received scores of 85, 88, 87, and 90 on her algebra tests. what is the minimum score she must receive on the fifth test to have an overall test score average of at least 87? write your answer as a number only.

Explanation:

Step1: Define variable for 5th score

Let $x$ = 5th test score.

Step2: Set up average inequality

$$\frac{85 + 88 + 87 + 90 + x}{5} \geq 87$$

Step3: Calculate sum of known scores

$85+88+87+90 = 350$

Step4: Simplify the inequality

$$\frac{350 + x}{5} \geq 87$$
Multiply both sides by 5: $350 + x \geq 435$

Step5: Solve for $x$

$x \geq 435 - 350$
$x \geq 85$

Answer:

85