Fill in the blanks.
The ratio of the number of girls to the number of boys in Class A is 7 : 4.
The ratio of the number of girls to the number of boys in Class B is 5 : 6.
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 |
7 x 5 |
4 x 5 |
5 x 7 |
6 x 7 |
35 u |
20 u |
35 u |
42 u |
(a)
Change ratio into units.
The number of girls in Class A and Class B is the same.
LCM of 7 and 5 = 35
Class A
Girls : Boys
7 : 4
(x5) 35 : 20
Class B
Girls : Boys
5 : 6
(x7) 35 : 42
Number of girls in Class A = 35 u
(b)
Number of boys in Class B = 42 u
(c)
Number of children in Class B
= 35 u + 42 u
= 77 u
(d)
Number of children in Class A
= 35 u + 20 u
= 55 u
Total number of children
= 77 u + 55 u
= 132 u
Answer(s): (a) 35; (b) 42; (c) 77; (d) 132