In a school field,
56 of the pupils wore sweaters. After 70 pupils who wore sweaters left the school field, the percentage of pupils who wore sweaters decreased to 60%. How many pupils in the school field did not wear sweaters?
| |
Wore sweaters |
Did not wear sweaters |
| Before |
5x2 =
10 u |
1x2 =
2 u |
| Change |
- 70 |
|
| After |
3x1 =
3 u |
2x1 =
2 u |
60% =
60100 =
35The number of pupils who did not wear sweaters remains unchanged. LCM of 1 and 2 is 2.
Number of pupils who wore sweaters and left
= 10 u - 3 u
= 7 u
7 u = 70
1 u = 70 ÷ 7 = 10
Number of pupils who did not wear sweaters
= 2 u
= 2 x 10
= 20
Answer(s): 20
