During a donation drive, $1490 was collected by 60 students. Each girl donated $30 and each boy donated $20. How many girls were there?
Number of
girls |
Amount collected
by girls |
Number of
boys |
Amount collected
by boys |
Total amount
collected |
60
|
60 x 30 =
$1800 |
0 |
0
|
$1800 |
59
|
59 x 30 =
$1770 |
1 |
1 x 20 =
$20 |
$1790 |
29
|
29 x 30 =
$870 |
31
|
31 x 20 =
$620 |
$1490
|
Total amount collected if all the donations were made by girls
= 60 x 30
= $1800
Big difference in the total amounts made between the girls and the boys
= 1800 - 1490
= $310
Small difference in the amount made between one girl and one boy
= 30 - 20
= $10
Number of boys
= 310 ÷ 10
= 31
Number of girls
= 60 - 31
= 29
Answer(s): 29
