In a school field,
27 of the boys wore vests. After 144 boys who wore vests entered the school field, the percentage of boys who wore vests increased to 80%. How many boys in the school field did not wear vests?
|
Wore vests |
Did not wear vests |
Before |
2x1 = 2 u |
5x1 = 5 u |
Change |
+ 144 |
|
After |
4x5 = 20 u |
1x5 = 5 u |
80% =
80100 =
45The number of boys who did not wear vests remains unchanged. LCM of 5 and 1 is 5.
Number of boys who wore vests and left
= 20 u - 2 u
= 18 u
18 u = 144
1 u = 144 ÷ 18 = 8
Number of boys who did not wear vests
= 5 u
= 5 x 8
= 40
Answer(s): 40