In a canteen,
35 of the boys wore cardigans. After 30 boys who wore cardigans entered the canteen, the percentage of boys who wore cardigans increased to 75%. How many boys in the canteen did not wear cardigans?
| |
Wore cardigans |
Did not wear cardigans |
| Before |
3x1 =
3 u |
2x1 =
2 u |
| Change |
+ 30 |
|
| After |
3x2 =
6 u |
1x2 =
2 u |
75% =
75100 =
34The number of boys who did not wear cardigans remains unchanged. LCM of 2 and 1 is 2.
Number of boys who wore cardigans and left
= 6 u - 3 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
Number of boys who did not wear cardigans
= 2 u
= 2 x 10
= 20
Answer(s): 20
