In a parade square,
57 of the students wore vests. After 143 students who wore vests entered the parade square, the percentage of students who wore vests increased to 90%. How many students in the parade square did not wear vests?
| |
Wore vests |
Did not wear vests |
| Before |
5x1 =
5 u |
2x1 =
2 u |
| Change |
+ 143 |
|
| After |
9x2 =
18 u |
1x2 =
2 u |
90% =
90100 =
910The number of students who did not wear vests remains unchanged. LCM of 2 and 1 is 2.
Number of students who wore vests and left
= 18 u - 5 u
= 13 u
13 u = 143
1 u = 143 ÷ 13 = 11
Number of students who did not wear vests
= 2 u
= 2 x 11
= 22
Answer(s): 22
