In a basketball court,
25 of the pupils wore sweaters. After 10 pupils who wore sweaters left the basketball court, the percentage of pupils who wore sweaters decreased to 30%. How many pupils in the basketball court did not wear sweaters?
| |
Wore sweaters |
Did not wear sweaters |
| Before |
2x7 =
14 u |
3x7 =
21 u |
| Change |
- 10 |
|
| After |
3x3 =
9 u |
7x3 =
21 u |
30% =
30100 =
310The number of pupils who did not wear sweaters remains unchanged. LCM of 3 and 7 is 21.
Number of pupils who wore sweaters and left
= 14 u - 9 u
= 5 u
5 u = 10
1 u = 10 ÷ 5 = 2
Number of pupils who did not wear sweaters
= 21 u
= 21 x 2
= 42
Answer(s): 42
