Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 4 : 1.
The ratio of the number of boys to the number of girls in Class B is 3 : 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 |
4 x 3 |
1 x 3 |
3 x 4 |
7 x 4 |
12 u |
3 u |
12 u |
28 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 4 and 3 = 12
Class A
Boys : Girls
4 : 1
(x3) 12 : 3
Class B
Boys : Girls
3 : 7
(x4) 12 : 28
Number of boys in Class A = 12 u
(b)
Number of girls in Class B = 28 u
(c)
Number of children in Class B
= 12 u + 28 u
= 40 u
(d)
Number of children in Class A
= 12 u + 3 u
= 15 u
Total number of children
= 40 u + 15 u
= 55 u
Answer(s): (a) 12; (b) 28; (c) 40; (d) 55