In a tuckshop,
110 of the girls wore glasses. After 80 girls who wore glasses entered the tuckshop, the percentage of girls who wore glasses increased to 70%. How many girls in the tuckshop did not wear glasses?
| |
Wore glasses |
Did not wear glasses |
| Before |
1x1 =
1 u |
9x1 =
9 u |
| Change |
+ 80 |
|
| After |
7x3 =
21 u |
3x3 =
9 u |
70% =
70100 =
710The number of girls who did not wear glasses remains unchanged. LCM of 9 and 3 is 9.
Number of girls who wore glasses and left
= 21 u - 1 u
= 20 u
20 u = 80
1 u = 80 ÷ 20 = 4
Number of girls who did not wear glasses
= 9 u
= 9 x 4
= 36
Answer(s): 36
