In a parade square,
29 of the girls wore cardigans. After 312 girls who wore cardigans entered the parade square, the percentage of girls who wore cardigans increased to 80%. How many girls in the parade square did not wear cardigans?
|
Wore cardigans |
Did not wear cardigans |
Before |
2x1 = 2 u |
7x1 = 7 u |
Change |
+ 312 |
|
After |
4x7 = 28 u |
1x7 = 7 u |
80% =
80100 =
45The number of girls who did not wear cardigans remains unchanged. LCM of 7 and 1 is 7.
Number of girls who wore cardigans and left
= 28 u - 2 u
= 26 u
26 u = 312
1 u = 312 ÷ 26 = 12
Number of girls who did not wear cardigans
= 7 u
= 7 x 12
= 84
Answer(s): 84