In a parade square,
25 of the pupils wore ties. After 50 pupils who wore ties left the parade square, the percentage of pupils who wore ties decreased to 20%. How many pupils in the parade square did not wear ties?
|
Wore ties |
Did not wear ties |
Before |
2x4 = 8 u |
3x4 = 12 u |
Change |
- 50 |
|
After |
1x3 = 3 u |
4x3 = 12 u |
20% =
20100 =
15The number of pupils who did not wear ties remains unchanged. LCM of 3 and 4 is 12.
Number of pupils who wore ties and left
= 8 u - 3 u
= 5 u
5 u = 50
1 u = 50 ÷ 5 = 10
Number of pupils who did not wear ties
= 12 u
= 12 x 10
= 120
Answer(s): 120