In a parade square,
35 of the students wore sweaters. After 120 students who wore sweaters entered the parade square, the percentage of students who wore sweaters increased to 90%. How many students in the parade square did not wear sweaters?
|
Wore sweaters |
Did not wear sweaters |
Before |
3x1 = 3 u |
2x1 = 2 u |
Change |
+ 120 |
|
After |
9x2 = 18 u |
1x2 = 2 u |
90% =
90100 =
910The number of students who did not wear sweaters remains unchanged. LCM of 2 and 1 is 2.
Number of students who wore sweaters and left
= 18 u - 3 u
= 15 u
15 u = 120
1 u = 120 ÷ 15 = 8
Number of students who did not wear sweaters
= 2 u
= 2 x 8
= 16
Answer(s): 16