The average test score of a class was 69 marks. After two students who scored an average marks of 97 marks transferred out of the class, the average score of the remaining students became 61 marks. How many students were there in the class at first?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 2 |
| Value |
69 |
61 |
| Total value |
69 u |
61 u - 122 |
Number of students at first = 1 u
Total score at first
= 1 u x 69
= 69 u
Total score of the 2 students
= 2 x 97
= 194
Total marks scored after 2 students transferred out
= 61 x (1 u - 2)
= 61 u - 122
69 u - 194 = 61 u - 122
69 u - 61 u = 194 - 122
8 u = 72
1 u = 72 ÷ 8 = 9
Number of students in the class at first
= 1 u
= 9
Answer(s): 9
