The average test score of a class was 63 marks. After five students who scored an average marks of 98 marks transferred out of the class, the average score of the remaining students became 58 marks. How many students were there in the class at first?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 5 |
| Value |
63 |
58 |
| Total value |
63 u |
58 u - 290 |
Number of students at first = 1 u
Total score at first
= 1 u x 63
= 63 u
Total score of the 5 students
= 5 x 98
= 490
Total marks scored after 5 students transferred out
= 58 x (1 u - 5)
= 58 u - 290
63 u - 490 = 58 u - 290
63 u - 58 u = 490 - 290
5 u = 200
1 u = 200 ÷ 5 = 40
Number of students in the class at first
= 1 u
= 40
Answer(s): 40
