The average amount of money collected by a group of students at a flag day event was $112. When another 9 students turned up to help, the total amount donated increased by $502 and the average amount of money collected became $89. 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 + 9 |
| Value |
112 |
89 |
| Total Value |
112 u + 502 |
89 u + 801 |
Number of students at first = 1 u
Total amount collected by the students at first
= 1 u x 112
= 112 u
Total amount collected by the students in the end
= 89 x (1 u + 9)
= 89 u + 801
112 u + 502 = 89 u + 801
112 u - 89 u = 801 - 502
23 u = 299
1 u = 299 ÷ 23 = 13
Number of students in the end
= 1 u + 9
= 13 + 9
= 22
Answer(s): 22
