Fifteen minutes ago, 80% of the pupils in a basketball court were boys. 24 pupils left the basketball court. As a result, the number of boys decreased by 20% and the number of girls decreased by 60%. How many pupils are in the basketball court at first?
|
Boys |
Girls |
Total |
Before |
5 u |
1 u |
6 u |
Change |
- 1 u |
- 0.6 u |
- 1.6 u |
After |
4 u |
0.4 u |
4.4 u |
80% =
80100 =
45Number of boys who left the basketball court
= 20% x 5 u
=
20100 x 5 u
= 1 u
Number of girls who left the basketball court
= 60% x 1 u
=
60100 x 1 u
= 0.6 u
Total number of pupils who left the basketball court
= 1 u + 0.6 u
= 1.6 u
1.6 u = 24
1 u = 24 ÷ 1.6 = 15
Number of pupils in the basketball court at first
= 5 u + 1 u
= 6 u
= 6 x 15
= 90
Answer(s): 90