Question 292486
A student earned scores of 83, 78, and 77 on three of four test. What must the student score on the fourth test to have an average(arithmetic mean) of exactly 80?
.
Let x = score on fourth test
then
(83+78+77+x)/4 = 80
(238+x)/4 = 80
238+x = 320
x = 320-238
x = 82