In a tuckshop,
710 of the girls wore vests. After 120 girls who wore vests entered the tuckshop, the percentage of girls who wore vests increased to 90%. How many girls in the tuckshop did not wear vests?
| |
Wore vests |
Did not wear vests |
| Before |
7x1 =
7 u |
3x1 =
3 u |
| Change |
+ 120 |
|
| After |
9x3 =
27 u |
1x3 =
3 u |
90% =
90100 =
910The number of girls who did not wear vests remains unchanged. LCM of 3 and 1 is 3.
Number of girls who wore vests and left
= 27 u - 7 u
= 20 u
20 u = 120
1 u = 120 ÷ 20 = 6
Number of girls who did not wear vests
= 3 u
= 3 x 6
= 18
Answer(s): 18
