In a canteen,
710 of the pupils wore vests. After 40 pupils who wore vests entered the canteen, the percentage of pupils who wore vests increased to 80%. How many pupils in the canteen did not wear vests?
|
Wore vests |
Did not wear vests |
Before |
7x1 = 7 u |
3x1 = 3 u |
Change |
+ 40 |
|
After |
4x3 = 12 u |
1x3 = 3 u |
80% =
80100 =
45The number of pupils who did not wear vests remains unchanged. LCM of 3 and 1 is 3.
Number of pupils who wore vests and left
= 12 u - 7 u
= 5 u
5 u = 40
1 u = 40 ÷ 5 = 8
Number of pupils who did not wear vests
= 3 u
= 3 x 8
= 24
Answer(s): 24