In a school field,
47 of the pupils wore cardigans. After 209 pupils who wore cardigans left the school field, the percentage of pupils who wore cardigans decreased to 30%. How many pupils in the school field did not wear cardigans?
|
Wore cardigans |
Did not wear cardigans |
Before |
4x7 = 28 u |
3x7 = 21 u |
Change |
- 209 |
|
After |
3x3 = 9 u |
7x3 = 21 u |
30% =
30100 =
310The number of pupils who did not wear cardigans remains unchanged. LCM of 3 and 7 is 21.
Number of pupils who wore cardigans and left
= 28 u - 9 u
= 19 u
19 u = 209
1 u = 209 ÷ 19 = 11
Number of pupils who did not wear cardigans
= 21 u
= 21 x 11
= 231
Answer(s): 231