Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 9 : 4.
The ratio of the number of boys to the number of girls in Class B is 4 : 5.
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 |
9 x 4 |
4 x 4 |
4 x 9 |
5 x 9 |
36 u |
16 u |
36 u |
45 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 9 and 4 = 36
Class A
Boys : Girls
9 : 4
(x4) 36 : 16
Class B
Boys : Girls
4 : 5
(x9) 36 : 45
Number of boys in Class A = 36 u
(b)
Number of girls in Class B = 45 u
(c)
Number of children in Class B
= 36 u + 45 u
= 81 u
(d)
Number of children in Class A
= 36 u + 16 u
= 52 u
Total number of children
= 81 u + 52 u
= 133 u
Answer(s): (a) 36; (b) 45; (c) 81; (d) 133