Question

The day of a quiz, only Michelle was absent. The

average(arithmetic mean) grade of the other

students was 85. When Michelle took a makeup

quiz, her grade was 30, which lowered the class's

average to 80. How many students are in the

class?


Please explain how to do this problem

Answer 1

x/c = 85

c = # students that didnt take a make up quiz
x = all other scores added

(x + 30) / (c + 1) = 80

x + 30 = 80(c+1)

x + 30 = 80c + 80
x = 80c + 50

So,

x = 85c

85c = 80c + 50
5c = 50
c = 10

Answer 2

10 + Michelle = 11 students

Answer 3

thank you so much!

Answer 4

yw