In a tuckshop,
37 of the pupils wore cardigans. After 52 pupils who wore cardigans entered the tuckshop, the percentage of pupils who wore cardigans increased to 80%. How many pupils in the tuckshop did not wear cardigans?
| |
Wore cardigans |
Did not wear cardigans |
| Before |
3x1 =
3 u |
4x1 =
4 u |
| Change |
+ 52 |
|
| After |
4x4 =
16 u |
1x4 =
4 u |
80% =
80100 =
45The number of pupils who did not wear cardigans remains unchanged. LCM of 4 and 1 is 4.
Number of pupils who wore cardigans and left
= 16 u - 3 u
= 13 u
13 u = 52
1 u = 52 ÷ 13 = 4
Number of pupils who did not wear cardigans
= 4 u
= 4 x 4
= 16
Answer(s): 16
