In a parade square,
710 of the students wore scarves. After 200 students who wore scarves entered the parade square, the percentage of students who wore scarves increased to 90%. How many students in the parade square did not wear scarves?
|
Wore scarves |
Did not wear scarves |
Before |
7x1 = 7 u |
3x1 = 3 u |
Change |
+ 200 |
|
After |
9x3 = 27 u |
1x3 = 3 u |
90% =
90100 =
910The number of students who did not wear scarves remains unchanged. LCM of 3 and 1 is 3.
Number of students who wore scarves and left
= 27 u - 7 u
= 20 u
20 u = 200
1 u = 200 ÷ 20 = 10
Number of students who did not wear scarves
= 3 u
= 3 x 10
= 30
Answer(s): 30