Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 9 : 5.
The ratio of the number of boys to the number of girls in Class B is 7 : 8.
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 7 |
5 x 7 |
7 x 9 |
8 x 9 |
63 u |
35 u |
63 u |
72 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 9 and 7 = 63
Class A
Boys : Girls
9 : 5
(x7) 63 : 35
Class B
Boys : Girls
7 : 8
(x9) 63 : 72
Number of boys in Class A = 63 u
(b)
Number of girls in Class B = 72 u
(c)
Number of children in Class B
= 63 u + 72 u
= 135 u
(d)
Number of children in Class A
= 63 u + 35 u
= 98 u
Total number of children
= 135 u + 98 u
= 233 u
Answer(s): (a) 63; (b) 72; (c) 135; (d) 233