The average test score of a class was 63 marks. After two pupils who scored an average marks of 96 marks transferred out of the class, the average score of the remaining pupils became 60 marks. How many pupils were there in the class in the end?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 2 |
| Value |
63 |
60 |
| Total value |
63 u |
60 u - 120 |
Number of pupils at first = 1 u
Total score at first
= 1 u x 63
= 63 u
Total score of the 2 pupils
= 2 x 96
= 192
Total marks scored after 2 pupils transferred out
= 60 x (1 u - 2)
= 60 u - 120
63 u - 192 = 60 u - 120
63 u - 60 u = 192 - 120
3 u = 72
1 u = 72 ÷ 3 = 24
Number of pupils in the class in the end
= 1 u - 2
= 24 - 2
= 22
Answer(s): 22
