The average amount of money collected by a group of pupils at a flag day event was $119. When another 11 pupils turned up to help, the total amount donated increased by $565 and the average amount of money collected became $88. 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 + 11 |
Value |
119 |
88 |
Total Value |
119 u + 565 |
88 u + 968 |
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
= 88 x (1 u + 11)
= 88 u + 968
119 u + 565 = 88 u + 968
119 u - 88 u = 968 - 565
31 u = 403
1 u = 403 ÷ 31 = 13
Number of pupils at first
= 1 u
= 13
Answer(s): 13