In a canteen,
57 of the boys wore ties. After 156 boys who wore ties entered the canteen, the percentage of boys who wore ties increased to 90%. How many boys in the canteen did not wear ties?
| |
Wore ties |
Did not wear ties |
| Before |
5x1 =
5 u |
2x1 =
2 u |
| Change |
+ 156 |
|
| After |
9x2 =
18 u |
1x2 =
2 u |
90% =
90100 =
910The number of boys who did not wear ties remains unchanged. LCM of 2 and 1 is 2.
Number of boys who wore ties and left
= 18 u - 5 u
= 13 u
13 u = 156
1 u = 156 ÷ 13 = 12
Number of boys who did not wear ties
= 2 u
= 2 x 12
= 24
Answer(s): 24
