In a hall,
710 of the boys wore vests. After 160 boys who wore vests left the hall, the percentage of boys who wore vests decreased to 10%. How many boys in the hall did not wear vests?
|
Wore vests |
Did not wear vests |
Before |
7x3 = 21 u |
3x3 = 9 u |
Change |
- 160 |
|
After |
1x1 = 1 u |
9x1 = 9 u |
10% =
10100 =
110The number of boys who did not wear vests remains unchanged. LCM of 3 and 9 is 9.
Number of boys who wore vests and left
= 21 u - 1 u
= 20 u
20 u = 160
1 u = 160 ÷ 20 = 8
Number of boys who did not wear vests
= 9 u
= 9 x 8
= 72
Answer(s): 72