The average test score of a class was 67 marks. After five pupils who scored an average marks of 94 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 - 5 |
Value |
67 |
52 |
Total value |
67 u |
52 u - 260 |
Number of pupils at first = 1 u
Total score at first
= 1 u x 67
= 67 u
Total score of the 5 pupils
= 5 x 94
= 470
Total marks scored after 5 pupils transferred out
= 52 x (1 u - 5)
= 52 u - 260
67 u - 470 = 52 u - 260
67 u - 52 u = 470 - 260
15 u = 210
1 u = 210 ÷ 15 = 14
Number of pupils in the class at first
= 1 u
= 14
Answer(s): 14