Seventeen minutes ago, 70% of the children in a parade square were boys. 58 children left the parade square. As a result, the number of boys decreased by 40% and the number of girls decreased by 60%. How many children are in the parade square 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 parade square
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of girls who left the parade square
= 60% x 3 u
=
60100 x 3 u
= 1.8 u
Total number of children who left the parade square
= 4 u + 1.8 u
= 5.8 u
5.8 u = 58
1 u = 58 ÷ 5.8 = 10
Number of children in the parade square at first
= 10 u + 3 u
= 13 u
= 13 x 10
= 130
Answer(s): 130