The average test score of a class was 69 marks. After four students who scored an average marks of 91 marks transferred out of the class, the average score of the remaining students became 58 marks. How many students were there in the class in the end?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 4 |
| Value |
69 |
58 |
| Total value |
69 u |
58 u - 232 |
Number of students at first = 1 u
Total score at first
= 1 u x 69
= 69 u
Total score of the 4 students
= 4 x 91
= 364
Total marks scored after 4 students transferred out
= 58 x (1 u - 4)
= 58 u - 232
69 u - 364 = 58 u - 232
69 u - 58 u = 364 - 232
11 u = 132
1 u = 132 ÷ 11 = 12
Number of students in the class in the end
= 1 u - 4
= 12 - 4
= 8
Answer(s): 8
