In a school field,
310 of the pupils wore ties. After 600 pupils who wore ties entered the school field, the percentage of pupils who wore ties increased to 90%. How many pupils in the school field did not wear ties?
|
Wore ties |
Did not wear ties |
Before |
3x1 = 3 u |
7x1 = 7 u |
Change |
+ 600 |
|
After |
9x7 = 63 u |
1x7 = 7 u |
90% =
90100 =
910The number of pupils who did not wear ties remains unchanged. LCM of 7 and 1 is 7.
Number of pupils who wore ties and left
= 63 u - 3 u
= 60 u
60 u = 600
1 u = 600 ÷ 60 = 10
Number of pupils who did not wear ties
= 7 u
= 7 x 10
= 70
Answer(s): 70