In a school field,
45 of the boys wore ties. After 75 boys who wore ties left the school field, the percentage of boys who wore ties decreased to 20%. How many boys in the school field did not wear ties?
|
Wore ties |
Did not wear ties |
Before |
4x4 = 16 u |
1x4 = 4 u |
Change |
- 75 |
|
After |
1x1 = 1 u |
4x1 = 4 u |
20% =
20100 =
15The number of boys who did not wear ties remains unchanged. LCM of 1 and 4 is 4.
Number of boys who wore ties and left
= 16 u - 1 u
= 15 u
15 u = 75
1 u = 75 ÷ 15 = 5
Number of boys who did not wear ties
= 4 u
= 4 x 5
= 20
Answer(s): 20