Seventeen minutes ago, 80% of the students in a tuckshop were boys. 34 students left the tuckshop. As a result, the number of boys decreased by 20% and the number of girls decreased by 70%. How many students are in the tuckshop at first?
| |
Boys |
Girls |
Total |
| Before |
5 u |
1 u |
6 u |
| Change |
- 1 u |
- 0.7 u |
- 1.7 u |
| After |
4 u |
0.3 u |
4.3 u |
80% =
80100 =
45Number of boys who left the tuckshop
= 20% x 5 u
=
20100 x 5 u
= 1 u
Number of girls who left the tuckshop
= 70% x 1 u
=
70100 x 1 u
= 0.7 u
Total number of students who left the tuckshop
= 1 u + 0.7 u
= 1.7 u
1.7 u = 34
1 u = 34 ÷ 1.7 = 20
Number of students in the tuckshop at first
= 5 u + 1 u
= 6 u
= 6 x 20
= 120
Answer(s): 120
