During a donation drive, $2510 was collected by 80 pupils. Each girl donated $40 and each boy donated $10. How many girls were there?
Number of girls |
Amount collected by girls |
Number of boys |
Amount collected by boys |
Total amount collected |
80
|
80 x 40 = $3200 |
0 |
0
|
$3200 |
79
|
79 x 40 = $3160 |
1 |
1 x 10 = $10 |
$3170 |
57
|
57 x 40 = $2280 |
23
|
23 x 10 = $230 |
$2510
|
Total amount collected if all the donations were made by girls
= 80 x 40
= $3200
Big difference in the total amounts made between the girls and the boys
= 3200 - 2510
= $690
Small difference in the amount made between one girl and one boy
= 40 - 10
= $30
Number of boys
= 690 ÷ 30
= 23
Number of girls
= 80 - 23
= 57
Answer(s): 57