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 5 : 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 5 |
1 x 5 |
5 x 4 |
7 x 4 |
20 u |
5 u |
20 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 5 = 20
Class A
Boys : Girls
4 : 1
(x5) 20 : 5
Class B
Boys : Girls
5 : 7
(x4) 20 : 28
Number of boys in Class A = 20 u
(b)
Number of girls in Class B = 28 u
(c)
Number of children in Class B
= 20 u + 28 u
= 48 u
(d)
Number of children in Class A
= 20 u + 5 u
= 25 u
Total number of children
= 48 u + 25 u
= 73 u
Answer(s): (a) 20; (b) 28; (c) 48; (d) 73