Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 7 : 6.
The ratio of the number of boys to the number of girls in Class B is 3 : 4.
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 |
7 x 3 |
6 x 3 |
3 x 7 |
4 x 7 |
21 u |
18 u |
21 u |
28 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 7 and 3 = 21
Class A
Boys : Girls
7 : 6
(x3) 21 : 18
Class B
Boys : Girls
3 : 4
(x7) 21 : 28
Number of boys in Class A = 21 u
(b)
Number of girls in Class B = 28 u
(c)
Number of children in Class B
= 21 u + 28 u
= 49 u
(d)
Number of children in Class A
= 21 u + 18 u
= 39 u
Total number of children
= 49 u + 39 u
= 88 u
Answer(s): (a) 21; (b) 28; (c) 49; (d) 88