In a school field,
49 of the students wore spectacles. After 117 students who wore spectacles left the school field, the percentage of students who wore spectacles decreased to 30%. How many students in the school field did not wear spectacles?
|
Wore spectacles |
Did not wear spectacles |
Before |
4x7 = 28 u |
5x7 = 35 u |
Change |
- 117 |
|
After |
3x5 = 15 u |
7x5 = 35 u |
30% =
30100 =
310The number of students who did not wear spectacles remains unchanged. LCM of 5 and 7 is 35.
Number of students who wore spectacles and left
= 28 u - 15 u
= 13 u
13 u = 117
1 u = 117 ÷ 13 = 9
Number of students who did not wear spectacles
= 35 u
= 35 x 9
= 315
Answer(s): 315