Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 3 : 2.
The ratio of the number of boys to the number of girls in Class B is 4 : 7.
The number of boys is the same.
- Number of boys in Class A = _____ u
- Number of girls in Class B = _____ u
- Number of children in Class B = _____ u
- Total number of children = _____ u
Class A |
Class B |
Boys |
Girls |
Boys |
Girls |
3 x 4 |
2 x 4 |
4 x 3 |
7 x 3 |
12 u |
8 u |
12 u |
21 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 3 and 4 = 12
Class A
Boys : Girls
3 : 2
(x4) 12 : 8
Class B
Boys : Girls
4 : 7
(x3) 12 : 21
Number of boys in Class A = 12 u
(b)
Number of girls in Class B = 21 u
(c)
Number of children in Class B
= 12 u + 21 u
= 33 u
(d)
Number of children in Class A
= 12 u + 8 u
= 20 u
Total number of children
= 33 u + 20 u
= 53 u
Answer(s): (a) 12; (b) 21; (c) 33; (d) 53