Question

1) A student scored 69,79, and 94 on three algebra tests. What must he score on the fourth test in order to have an average grade of at least 85?

Answer 1

He must score at least 98

Explanation:

The three test scores = 69, 79, 94

let the fourth test = y

Average = sum of scores/number of scores

Sum of the 4 scores = 69 + 79 + 94 + y

number of scores = 4

Average of atleast 85 means the minimum score in the fourth should be 85

$\text{Average}=\frac{69+79+94+y}{4}$$\begin{gathered} 85\text{ = }\frac{242+y}{4} \\ \text{cross multiply:} \\ 85(4)\text{ = 242 + y} \end{gathered}$

340 = 242 + y

subtract 242 from both sides:

340 -242 = 242 - 242 + y

98 = 0 + y

y = 98

This means the minimum score the student needs to get to have an average grade of at least 85 is 98