Average Practice Test 6

Average of test score of class m student = 70
Total score = 70m
Average of class n student = 91
Total score = 91n
Average of the combined class = (m + n) = 80
Total score = (m + n) 80
According to the statement,
70m + 91n = 80 (m + n)
70m + 91n = 80m + 80n
91n - 80n = 80m - 70m
11n = 10m

n

m

=

10

11