In a parade square,
12 of the pupils wore glasses. After 20 pupils who wore glasses left the parade square, the percentage of pupils who wore glasses decreased to 45%. How many pupils in the parade square did not wear glasses?
|
Wore glasses |
Did not wear glasses |
Before |
1x11 = 11 u |
1x11 = 11 u |
Change |
- 20 |
|
After |
9x1 = 9 u |
11x1 = 11 u |
45% =
45100 =
920The number of pupils who did not wear glasses remains unchanged. LCM of 1 and 11 is 11.
Number of pupils who wore glasses and left
= 11 u - 9 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Number of pupils who did not wear glasses
= 11 u
= 11 x 10
= 110
Answer(s): 110