In a parade square,
79 of the pupils wore sweaters. After 177 pupils who wore sweaters left the parade square, the percentage of pupils who wore sweaters decreased to 45%. How many pupils in the parade square did not wear sweaters?
| |
Wore sweaters |
Did not wear sweaters |
| Before |
7x11 =
77 u |
2x11 =
22 u |
| Change |
- 177 |
|
| After |
9x2 =
18 u |
11x2 =
22 u |
45% =
45100 =
920The number of pupils who did not wear sweaters remains unchanged. LCM of 2 and 11 is 22.
Number of pupils who wore sweaters and left
= 77 u - 18 u
= 59 u
59 u = 177
1 u = 177 ÷ 59 = 3
Number of pupils who did not wear sweaters
= 22 u
= 22 x 3
= 66
Answer(s): 66
