An instructor has graded 21 exam papers submitted by student

An instructor has graded 21 exam papers submitted by students in a class of 22 students, and the average so far is 68. (The maximum possible score is 100.) How high would the score on the last paper have to be to raise the class average by 1 point?


By 2 points?

Solution

Total Mark of the 21 Students

Total/21= 68 --> Total = 21*68= 1428

Raise By One Point

69 = (1428+x)/22
x = 90

Raise By Two Points

70 = (1562+x)/22
x = -22 (Not Possible)