The average amount of money collected by a group of students at a flag day event was $116. When another 15 students turned up to help, the total amount donated increased by $841 and the average amount of money collected became $85. How many students were there in the group at first?
| |
Number of students
at first |
Number of students
in the end |
| Number |
1 u |
1 u + 15 |
| Value |
116 |
85 |
| Total Value |
116 u + 841 |
85 u + 1275 |
Number of students at first = 1 u
Total amount collected by the students at first
= 1 u x 116
= 116 u
Total amount collected by the students in the end
= 85 x (1 u + 15)
= 85 u + 1275
116 u + 841 = 85 u + 1275
116 u - 85 u = 1275 - 841
31 u = 434
1 u = 434 ÷ 31 = 14
Number of students at first
= 1 u
= 14
Answer(s): 14
