In a basketball court,
310 of the boys wore cardigans. After 80 boys who wore cardigans entered the basketball court, the percentage of boys who wore cardigans increased to 70%. How many boys in the basketball court did not wear cardigans?
|
Wore cardigans |
Did not wear cardigans |
Before |
3x3 = 9 u |
7x3 = 21 u |
Change |
+ 80 |
|
After |
7x7 = 49 u |
3x7 = 21 u |
70% =
70100 =
710The number of boys who did not wear cardigans remains unchanged. LCM of 7 and 3 is 21.
Number of boys who wore cardigans and left
= 49 u - 9 u
= 40 u
40 u = 80
1 u = 80 ÷ 40 = 2
Number of boys who did not wear cardigans
= 21 u
= 21 x 2
= 42
Answer(s): 42