The average amount of money collected by a group of pupils at a flag day event was $118. When another 14 pupils turned up to help, the total amount donated increased by $985 and the average amount of money collected became $89. How many pupils were there in the group in the end?
|
Number of pupils at first |
Number of pupils in the end |
Number |
1 u |
1 u + 14 |
Value |
118 |
89 |
Total Value |
118 u + 985 |
89 u + 1246 |
Number of pupils at first = 1 u
Total amount collected by the pupils at first
= 1 u x 118
= 118 u
Total amount collected by the pupils in the end
= 89 x (1 u + 14)
= 89 u + 1246
118 u + 985 = 89 u + 1246
118 u - 89 u = 1246 - 985
29 u = 261
1 u = 261 ÷ 29 = 9
Number of pupils in the end
= 1 u + 14
= 9 + 14
= 23
Answer(s): 23