Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 8 : 7.
The ratio of the number of boys to the number of girls in Class B is 9 : 10.
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 |
8 x 9 |
7 x 9 |
9 x 8 |
10 x 8 |
72 u |
63 u |
72 u |
80 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 8 and 9 = 72
Class A
Boys : Girls
8 : 7
(x9) 72 : 63
Class B
Boys : Girls
9 : 10
(x8) 72 : 80
Number of boys in Class A = 72 u
(b)
Number of girls in Class B = 80 u
(c)
Number of children in Class B
= 72 u + 80 u
= 152 u
(d)
Number of children in Class A
= 72 u + 63 u
= 135 u
Total number of children
= 152 u + 135 u
= 287 u
Answer(s): (a) 72; (b) 80; (c) 152; (d) 287