The average test score of a class was 68 marks. After two pupils who scored an average marks of 92 marks transferred out of the class, the average score of the remaining pupils became 52 marks. How many pupils were there in the class at first?
|
(1) |
(2) |
Number |
1 u |
1 u - 2 |
Value |
68 |
52 |
Total value |
68 u |
52 u - 104 |
Number of pupils at first = 1 u
Total score at first
= 1 u x 68
= 68 u
Total score of the 2 pupils
= 2 x 92
= 184
Total marks scored after 2 pupils transferred out
= 52 x (1 u - 2)
= 52 u - 104
68 u - 184 = 52 u - 104
68 u - 52 u = 184 - 104
16 u = 80
1 u = 80 ÷ 16 = 5
Number of pupils in the class at first
= 1 u
= 5
Answer(s): 5