During a donation drive, $1600 was collected by 80 pupils. Each boy donated $30 and each girl donated $10. How many boys were there?
Number of boys |
Amount collected by boys |
Number of girls |
Amount collected by girls |
Total amount collected |
80
|
80 x 30 = $2400 |
0 |
0
|
$2400 |
79
|
79 x 30 = $2370 |
1 |
1 x 10 = $10 |
$2380 |
40
|
40 x 30 = $1200 |
40
|
40 x 10 = $400 |
$1600
|
Total amount collected if all the donations were made by boys
= 80 x 30
= $2400
Big difference in the total amounts made between the boys and the girls
= 2400 - 1600
= $800
Small difference in the amount made between one boy and one girl
= 30 - 10
= $20
Number of girls
= 800 ÷ 20
= 40
Number of boys
= 80 - 40
= 40
Answer(s): 40