The average test score of a class was 66 marks. After four students who scored an average marks of 96 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 - 4 |
| Value |
66 |
63 |
| Total value |
66 u |
63 u - 252 |
Number of students at first = 1 u
Total score at first
= 1 u x 66
= 66 u
Total score of the 4 students
= 4 x 96
= 384
Total marks scored after 4 students transferred out
= 63 x (1 u - 4)
= 63 u - 252
66 u - 384 = 63 u - 252
66 u - 63 u = 384 - 252
3 u = 132
1 u = 132 ÷ 3 = 44
Number of students in the class in the end
= 1 u - 4
= 44 - 4
= 40
Answer(s): 40
