Sixteen minutes ago, 70% of the students in a tuckshop were boys. 19 students left the tuckshop. As a result, the number of boys decreased by 20% and the number of girls decreased by 60%. How many students are in the tuckshop at first?
| |
Boys |
Girls |
Total |
| Before |
10 u |
3 u |
13 u |
| Change |
- 2 u |
- 1.8 u |
- 3.8 u |
| After |
8 u |
1.2 u |
9.2 u |
70% =
70100 =
710Number of boys who left the tuckshop
= 20% x 10 u
=
20100 x 10 u
= 2 u
Number of girls who left the tuckshop
= 60% x 3 u
=
60100 x 3 u
= 1.8 u
Total number of students who left the tuckshop
= 2 u + 1.8 u
= 3.8 u
3.8 u = 19
1 u = 19 ÷ 3.8 = 5
Number of students in the tuckshop at first
= 10 u + 3 u
= 13 u
= 13 x 5
= 65
Answer(s): 65
