Fill in the blanks.
The ratio of the number of girls to the number of boys in Class A is 3 : 1.
The ratio of the number of girls to the number of boys in Class B is 7 : 8.
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 |
3 x 7 |
1 x 7 |
7 x 3 |
8 x 3 |
21 u |
7 u |
21 u |
24 u |
(a)
Change ratio into units.
The number of girls in Class A and Class B is the same.
LCM of 3 and 7 = 21
Class A
Girls : Boys
3 : 1
(x7) 21 : 7
Class B
Girls : Boys
7 : 8
(x3) 21 : 24
Number of girls in Class A = 21 u
(b)
Number of boys in Class B = 24 u
(c)
Number of children in Class B
= 21 u + 24 u
= 45 u
(d)
Number of children in Class A
= 21 u + 7 u
= 28 u
Total number of children
= 45 u + 28 u
= 73 u
Answer(s): (a) 21; (b) 24; (c) 45; (d) 73