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 $681 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 + 13 |
Value |
105 |
87 |
Total Value |
105 u + 681 |
87 u + 1131 |
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
= 87 x (1 u + 13)
= 87 u + 1131
105 u + 681 = 87 u + 1131
105 u - 87 u = 1131 - 681
18 u = 450
1 u = 450 ÷ 18 = 25
Number of students in the end
= 1 u + 13
= 25 + 13
= 38
Answer(s): 38