During a donation drive, $2720 was collected by 80 pupils. Each boy donated $40 and each girl donated $20. 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 40 =
$3200 |
0 |
0
|
$3200 |
79
|
79 x 40 =
$3160 |
1 |
1 x 20 =
$20 |
$3180 |
56
|
56 x 40 =
$2240 |
24
|
24 x 20 =
$480 |
$2720
|
Total amount collected if all the donations were made by boys
= 80 x 40
= $3200
Big difference in the total amounts made between the boys and the girls
= 3200 - 2720
= $480
Small difference in the amount made between one boy and one girl
= 40 - 20
= $20
Number of girls
= 480 ÷ 20
= 24
Number of boys
= 80 - 24
= 56
Answer(s): 56
