In a parade square,
710 of the students wore cardigans. After 40 students who wore cardigans left the parade square, the percentage of students who wore cardigans decreased to 50%. How many students in the parade square did not wear cardigans?
|
Wore cardigans |
Did not wear cardigans |
Before |
7x1 = 7 u |
3x1 = 3 u |
Change |
- 40 |
|
After |
1x3 = 3 u |
1x3 = 3 u |
50% =
50100 =
12The number of students who did not wear cardigans remains unchanged. LCM of 3 and 1 is 3.
Number of students who wore cardigans and left
= 7 u - 3 u
= 4 u
4 u = 40
1 u = 40 ÷ 4 = 10
Number of students who did not wear cardigans
= 3 u
= 3 x 10
= 30
Answer(s): 30