The average test score of a class was 63 marks. After four students who scored an average marks of 93 marks transferred out of the class, the average score of the remaining students became 51 marks. How many students were there in the class at first?
| |
(1) |
(2) |
| Number |
1 u |
1 u - 4 |
| Value |
63 |
51 |
| Total value |
63 u |
51 u - 204 |
Number of students at first = 1 u
Total score at first
= 1 u x 63
= 63 u
Total score of the 4 students
= 4 x 93
= 372
Total marks scored after 4 students transferred out
= 51 x (1 u - 4)
= 51 u - 204
63 u - 372 = 51 u - 204
63 u - 51 u = 372 - 204
12 u = 168
1 u = 168 ÷ 12 = 14
Number of students in the class at first
= 1 u
= 14
Answer(s): 14
