The average amount of money collected by a group of students at a flag day event was $105. When another 13 students turned up to help, the total amount donated increased by $765 and the average amount of money collected became $80. 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 + 13 |
| Value |
105 |
80 |
| Total Value |
105 u + 765 |
80 u + 1040 |
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
= 80 x (1 u + 13)
= 80 u + 1040
105 u + 765 = 80 u + 1040
105 u - 80 u = 1040 - 765
25 u = 275
1 u = 275 ÷ 25 = 11
Number of students in the end
= 1 u + 13
= 11 + 13
= 24
Answer(s): 24
