The average amount of money collected by a group of students at a flag day event was $101. When another 13 students turned up to help, the total amount donated increased by $515 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 |
101 |
80 |
Total Value |
101 u + 515 |
80 u + 1040 |
Number of students at first = 1 u
Total amount collected by the students at first
= 1 u x 101
= 101 u
Total amount collected by the students in the end
= 80 x (1 u + 13)
= 80 u + 1040
101 u + 515 = 80 u + 1040
101 u - 80 u = 1040 - 515
21 u = 525
1 u = 525 ÷ 21 = 25
Number of students in the end
= 1 u + 13
= 25 + 13
= 38
Answer(s): 38