During a donation drive, $2080 was collected by 50 pupils. Each girl donated $50 and each boy donated $30. How many girls were there?
Number of
girls |
Amount collected
by girls |
Number of
boys |
Amount collected
by boys |
Total amount
collected |
50
|
50 x 50 =
$2500 |
0 |
0
|
$2500 |
49
|
49 x 50 =
$2450 |
1 |
1 x 30 =
$30 |
$2480 |
29
|
29 x 50 =
$1450 |
21
|
21 x 30 =
$630 |
$2080
|
Total amount collected if all the donations were made by girls
= 50 x 50
= $2500
Big difference in the total amounts made between the girls and the boys
= 2500 - 2080
= $420
Small difference in the amount made between one girl and one boy
= 50 - 30
= $20
Number of boys
= 420 ÷ 20
= 21
Number of girls
= 50 - 21
= 29
Answer(s): 29
