Fill in the blanks.
The ratio of the number of girls to the number of boys in Class A is 2 : 1.
The ratio of the number of girls to the number of boys in Class B is 9 : 10.
The number of girls is the same.
- Number of girls in Class A = _____ u
- Number of boys in Class B = _____ u
- Number of children in Class B = _____ u
- Total number of children = _____ u
Class A |
Class B |
Girls |
Boys |
Girls |
Boys |
2 x 9 |
1 x 9 |
9 x 2 |
10 x 2 |
18 u |
9 u |
18 u |
20 u |
(a)
Change ratio into units.
The number of girls in Class A and Class B is the same.
LCM of 2 and 9 = 18
Class A
Girls : Boys
2 : 1
(x9) 18 : 9
Class B
Girls : Boys
9 : 10
(x2) 18 : 20
Number of girls in Class A = 18 u
(b)
Number of boys in Class B = 20 u
(c)
Number of children in Class B
= 18 u + 20 u
= 38 u
(d)
Number of children in Class A
= 18 u + 9 u
= 27 u
Total number of children
= 38 u + 27 u
= 65 u
Answer(s): (a) 18; (b) 20; (c) 38; (d) 65