The average test score of a class was 60 marks. After five students who scored an average marks of 95 marks transferred out of the class, the average score of the remaining students became 55 marks. How many students were there in the class at first?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 5 |
| Value |
60 |
55 |
| Total value |
60 u |
55 u - 275 |
Number of students at first = 1 u
Total score at first
= 1 u x 60
= 60 u
Total score of the 5 students
= 5 x 95
= 475
Total marks scored after 5 students transferred out
= 55 x (1 u - 5)
= 55 u - 275
60 u - 475 = 55 u - 275
60 u - 55 u = 475 - 275
5 u = 200
1 u = 200 ÷ 5 = 40
Number of students in the class at first
= 1 u
= 40
Answer(s): 40
