In a tuckshop,
13 of the pupils wore scarves. After 77 pupils who wore scarves entered the tuckshop, the percentage of pupils who wore scarves increased to 80%. How many pupils in the tuckshop did not wear scarves?
|
Wore scarves |
Did not wear scarves |
Before |
1x1 = 1 u |
2x1 = 2 u |
Change |
+ 77 |
|
After |
4x2 = 8 u |
1x2 = 2 u |
80% =
80100 =
45The number of pupils who did not wear scarves remains unchanged. LCM of 2 and 1 is 2.
Number of pupils who wore scarves and left
= 8 u - 1 u
= 7 u
7 u = 77
1 u = 77 ÷ 7 = 11
Number of pupils who did not wear scarves
= 2 u
= 2 x 11
= 22
Answer(s): 22