The average test score of a class was 56 marks. After four pupils who scored an average marks of 96 marks transferred out of the class, the average score of the remaining pupils became 52 marks. How many pupils were there in the class in the end?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 4 |
| Value |
56 |
52 |
| Total value |
56 u |
52 u - 208 |
Number of pupils at first = 1 u
Total score at first
= 1 u x 56
= 56 u
Total score of the 4 pupils
= 4 x 96
= 384
Total marks scored after 4 pupils transferred out
= 52 x (1 u - 4)
= 52 u - 208
56 u - 384 = 52 u - 208
56 u - 52 u = 384 - 208
4 u = 176
1 u = 176 ÷ 4 = 44
Number of pupils in the class in the end
= 1 u - 4
= 44 - 4
= 40
Answer(s): 40
