PLEASE HELP PLEASE HELP PLEASEEEE

Answer:
27. C
28. D
Step-by-step explanation:
The average of all grades in his fencing class, including the upcoming one, (all grades summed up divided by the amount of grades) must be equal to 86 (percent), hence C is the right answer for 27.
Solving this equation gives:
[tex]\frac{75+88+62+100+x}{5} = 86\\325 + x = 86 \cdot 5\\x = 430 - 325 = 105[/tex]
So D is the right answer for 28.