The average amount of money collected by a group of students at a flag day event was $117. When another 12 students turned up to help, the total amount donated increased by $522 and the average amount of money collected became $75. 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 + 12 |
Value |
117 |
75 |
Total Value |
117 u + 522 |
75 u + 900 |
Number of students at first = 1 u
Total amount collected by the students at first
= 1 u x 117
= 117 u
Total amount collected by the students in the end
= 75 x (1 u + 12)
= 75 u + 900
117 u + 522 = 75 u + 900
117 u - 75 u = 900 - 522
42 u = 378
1 u = 378 ÷ 42 = 9
Number of students in the end
= 1 u + 12
= 9 + 12
= 21
Answer(s): 21