Answer:
D. 64
Step-by-step explanation:
Setup an equation to solve for the missing test, x. Since you are doing average and there are three tests, divide the left side of the equation by 3. Set the equation equal to 60 since that is what we want the average to be.
[tex]\frac{52+64+x}{3}=60[/tex]
Multiply both sides by 3 to remove it from the denominator.
[tex](3)\frac{52+64+x}{3}=60(3)[/tex]
[tex]52+64+x=180[/tex]
Simplify and solve for x.
[tex]52+64+x=180\\116+x=180\\116-116+x=180-116\\x=64[/tex]
