The average amount of money collected by a group of pupils at a flag day event was $119. When another 15 pupils turned up to help, the total amount donated increased by $935 and the average amount of money collected became $85. How many pupils were there in the group at first?
|
Number of pupils at first |
Number of pupils in the end |
Number |
1 u |
1 u + 15 |
Value |
119 |
85 |
Total Value |
119 u + 935 |
85 u + 1275 |
Number of pupils at first = 1 u
Total amount collected by the pupils at first
= 1 u x 119
= 119 u
Total amount collected by the pupils in the end
= 85 x (1 u + 15)
= 85 u + 1275
119 u + 935 = 85 u + 1275
119 u - 85 u = 1275 - 935
34 u = 340
1 u = 340 ÷ 34 = 10
Number of pupils at first
= 1 u
= 10
Answer(s): 10