The average test score of a class was 66 marks. After two students who scored an average marks of 90 marks transferred out of the class, the average score of the remaining students became 63 marks. How many students were there in the class in the end?
|
(1) |
(2) |
Number |
1 u |
1 u - 2 |
Value |
66 |
63 |
Total value |
66 u |
63 u - 126 |
Number of students at first = 1 u
Total score at first
= 1 u x 66
= 66 u
Total score of the 2 students
= 2 x 90
= 180
Total marks scored after 2 students transferred out
= 63 x (1 u - 2)
= 63 u - 126
66 u - 180 = 63 u - 126
66 u - 63 u = 180 - 126
3 u = 54
1 u = 54 ÷ 3 = 18
Number of students in the class in the end
= 1 u - 2
= 18 - 2
= 16
Answer(s): 16