In a school field,
12 of the children wore scarves. After 20 children who wore scarves left the school field, the percentage of children who wore scarves decreased to 25%. How many children in the school field did not wear scarves?
| |
Wore scarves |
Did not wear scarves |
| Before |
1x3 =
3 u |
1x3 =
3 u |
| Change |
- 20 |
|
| After |
1x1 =
1 u |
3x1 =
3 u |
25% =
25100 =
14The number of children who did not wear scarves remains unchanged. LCM of 1 and 3 is 3.
Number of children who wore scarves and left
= 3 u - 1 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Number of children who did not wear scarves
= 3 u
= 3 x 10
= 30
Answer(s): 30
