Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 10 : 3.
The ratio of the number of boys to the number of girls in Class B is 4 : 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 |
10 x 2 |
3 x 2 |
4 x 5 |
7 x 5 |
20 u |
6 u |
20 u |
35 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 10 and 4 = 20
Class A
Boys : Girls
10 : 3
(x2) 20 : 6
Class B
Boys : Girls
4 : 7
(x5) 20 : 35
Number of boys in Class A = 20 u
(b)
Number of girls in Class B = 35 u
(c)
Number of children in Class B
= 20 u + 35 u
= 55 u
(d)
Number of children in Class A
= 20 u + 6 u
= 26 u
Total number of children
= 55 u + 26 u
= 81 u
Answer(s): (a) 20; (b) 35; (c) 55; (d) 81