Question

6. Ali must average 90 on all 5 quizzes in order to earn an A in her MAT097 Foundations ofAlgebra class. She scored 90, 87, 93 and 85 on the first 4 quizzes. What is the least she mustscore on the fifth quiz in order to get an A? (5 points)

Answer 1

Step 1

State the formula for the average that can be used for this problem

$\begin{gathered} \text{Average}=\frac{x+y+z+a+b}{5} \\ \text{where} \\ x=90 \\ y=87 \\ z=93 \\ a=85 \\ b=\text{ required score to get an average of 90 in the 5 quizzez} \\ \text{Average = 90} \end{gathered}$

Step 2

Find the value of b

$90=\frac{90+87+93+85+b}{5}$

$\begin{gathered} 90(5)=355+b \\ 450\text{ = 355+b} \end{gathered}$

$\begin{gathered} 450-355=b \\ b=95 \end{gathered}$

Hence, the least score she must get in the fifth test in order to get an A by having an average of 90 = 95

Answer = 95