Six minutes ago, 60% of the pupils in a tuckshop were girls. 16 pupils left the tuckshop. As a result, the number of girls decreased by 40% and the number of boys decreased by 60%. How many pupils are in the tuckshop at first?
| |
Girls |
Boys |
Total |
| Before |
5 u |
2 u |
7 u |
| Change |
- 2 u |
- 1.2 u |
- 3.2 u |
| After |
3 u |
0.8 u |
3.8 u |
60% =
60100 =
35Number of girls who left the tuckshop
= 40% x 5 u
=
40100 x 5 u
= 2 u
Number of boys who left the tuckshop
= 60% x 2 u
=
60100 x 2 u
= 1.2 u
Total number of pupils who left the tuckshop
= 2 u + 1.2 u
= 3.2 u
3.2 u = 16
1 u = 16 ÷ 3.2 = 5
Number of pupils in the tuckshop at first
= 5 u + 2 u
= 7 u
= 7 x 5
= 35
Answer(s): 35
