Eight minutes ago, 70% of the students in a canteen were boys. 29 students left the canteen. As a result, the number of boys decreased by 40% and the number of girls decreased by 60%. How many students are in the canteen at first?
| |
Boys |
Girls |
Total |
| Before |
10 u |
3 u |
13 u |
| Change |
- 4 u |
- 1.8 u |
- 5.8 u |
| After |
6 u |
1.2 u |
7.2 u |
70% =
70100 =
710Number of boys who left the canteen
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of girls who left the canteen
= 60% x 3 u
=
60100 x 3 u
= 1.8 u
Total number of students who left the canteen
= 4 u + 1.8 u
= 5.8 u
5.8 u = 29
1 u = 29 ÷ 5.8 = 5
Number of students in the canteen at first
= 10 u + 3 u
= 13 u
= 13 x 5
= 65
Answer(s): 65
