The average amount of money collected by a group of students at a flag day event was $109. When another 12 students turned up to help, the total amount donated increased by $758 and the average amount of money collected became $87. 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 |
109 |
87 |
| Total Value |
109 u + 758 |
87 u + 1044 |
Number of students at first = 1 u
Total amount collected by the students at first
= 1 u x 109
= 109 u
Total amount collected by the students in the end
= 87 x (1 u + 12)
= 87 u + 1044
109 u + 758 = 87 u + 1044
109 u - 87 u = 1044 - 758
22 u = 286
1 u = 286 ÷ 22 = 13
Number of students in the end
= 1 u + 12
= 13 + 12
= 25
Answer(s): 25
