The average amount of money collected by a group of students at a flag day event was $105. When another 12 students turned up to help, the total amount donated increased by $685 and the average amount of money collected became $82. How many students were there in the group in the end?
|
Number of students at first |
Number of students in the end |
Number |
1 u |
1 u + 12 |
Value |
105 |
82 |
Total Value |
105 u + 685 |
82 u + 984 |
Number of students at first = 1 u
Total amount collected by the students at first
= 1 u x 105
= 105 u
Total amount collected by the students in the end
= 82 x (1 u + 12)
= 82 u + 984
105 u + 685 = 82 u + 984
105 u - 82 u = 984 - 685
23 u = 299
1 u = 299 ÷ 23 = 13
Number of students in the end
= 1 u + 12
= 13 + 12
= 25
Answer(s): 25