In a basketball court,
13 of the boys wore scarves. After 51 boys who wore scarves entered the basketball court, the percentage of boys who wore scarves increased to 90%. How many boys in the basketball court did not wear scarves?
|
Wore scarves |
Did not wear scarves |
Before |
1x1 = 1 u |
2x1 = 2 u |
Change |
+ 51 |
|
After |
9x2 = 18 u |
1x2 = 2 u |
90% =
90100 =
910The number of boys who did not wear scarves remains unchanged. LCM of 2 and 1 is 2.
Number of boys who wore scarves and left
= 18 u - 1 u
= 17 u
17 u = 51
1 u = 51 ÷ 17 = 3
Number of boys who did not wear scarves
= 2 u
= 2 x 3
= 6
Answer(s): 6