In a tuckshop,
13 of the girls wore spectacles. After 77 girls who wore spectacles entered the tuckshop, the percentage of girls who wore spectacles increased to 80%. How many girls in the tuckshop did not wear spectacles?
| |
Wore spectacles |
Did not wear spectacles |
| Before |
1x1 =
1 u |
2x1 =
2 u |
| Change |
+ 77 |
|
| After |
4x2 =
8 u |
1x2 =
2 u |
80% =
80100 =
45The number of girls who did not wear spectacles remains unchanged. LCM of 2 and 1 is 2.
Number of girls who wore spectacles and left
= 8 u - 1 u
= 7 u
7 u = 77
1 u = 77 ÷ 7 = 11
Number of girls who did not wear spectacles
= 2 u
= 2 x 11
= 22
Answer(s): 22
