Fill in the blanks.
Number of boys at first is 80% of the children.
Number of boys is then decreased to 70% of the children.
- Number of boys at first = _____ u
- Number of boys in the end = _____ u
- Decrease in the number of boys = _____ u
- Number of children in the end = _____ u
|
Boys |
Girls |
Before |
4 x 3 = 12 u |
1 x 3 = 3 u |
Change |
- ? |
No change |
After |
7 x 1 = 7 u |
3 x 1 = 3 u |
(a)
Change percentage into units.
80% =
80100 =
4570% =
70100 =
710 Fraction of the children who are girls at first
= 1 -
45=
15 Fraction of the children who are girls in the end
= 1 -
710=
310Number of girls at first and in the end remains the same.
The number of girls is the unchanged quantity.
LCM of 1 and 3 = 3
Number of boys at first = 12 u
(b)
Number of boys in the end = 7 u
(c)
Decrease in the number of boys
= 12 u - 7 u
= 5 u
(d)
Number of children in the end
= 7 u + 3 u
= 10 u
Answer(s): (a) 12; (b) 7; (c) 5; (d) 10