During a donation drive, $1840 was collected by 80 students. 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 |
52
|
52 x 30 =
$1560 |
28
|
28 x 10 =
$280 |
$1840
|
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 - 1840
= $560
Small difference in the amount made between one boy and one girl
= 30 - 10
= $20
Number of girls
= 560 ÷ 20
= 28
Number of boys
= 80 - 28
= 52
Answer(s): 52
