In a parade square,
89 of the pupils wore sweaters. After 115 pupils who wore sweaters left the parade square, the percentage of pupils who wore sweaters decreased to 25%. How many pupils in the parade square did not wear sweaters?
| |
Wore sweaters |
Did not wear sweaters |
| Before |
8x3 =
24 u |
1x3 =
3 u |
| Change |
- 115 |
|
| After |
1x1 =
1 u |
3x1 =
3 u |
25% =
25100 =
14The number of pupils who did not wear sweaters remains unchanged. LCM of 1 and 3 is 3.
Number of pupils who wore sweaters and left
= 24 u - 1 u
= 23 u
23 u = 115
1 u = 115 ÷ 23 = 5
Number of pupils who did not wear sweaters
= 3 u
= 3 x 5
= 15
Answer(s): 15
