The average test score of a class was 61 marks. After two students who scored an average marks of 91 marks transferred out of the class, the average score of the remaining students became 56 marks. How many students were there in the class in the end?
|
(1) |
(2) |
Number |
1 u |
1 u - 2 |
Value |
61 |
56 |
Total value |
61 u |
56 u - 112 |
Number of students at first = 1 u
Total score at first
= 1 u x 61
= 61 u
Total score of the 2 students
= 2 x 91
= 182
Total marks scored after 2 students transferred out
= 56 x (1 u - 2)
= 56 u - 112
61 u - 182 = 56 u - 112
61 u - 56 u = 182 - 112
5 u = 70
1 u = 70 ÷ 5 = 14
Number of students in the class in the end
= 1 u - 2
= 14 - 2
= 12
Answer(s): 12