Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 7 : 5.
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 |
7 x 9 |
5 x 9 |
9 x 7 |
10 x 7 |
63 u |
45 u |
63 u |
70 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 7 and 9 = 63
Class A
Boys : Girls
7 : 5
(x9) 63 : 45
Class B
Boys : Girls
9 : 10
(x7) 63 : 70
Number of boys in Class A = 63 u
(b)
Number of girls in Class B = 70 u
(c)
Number of children in Class B
= 63 u + 70 u
= 133 u
(d)
Number of children in Class A
= 63 u + 45 u
= 108 u
Total number of children
= 133 u + 108 u
= 241 u
Answer(s): (a) 63; (b) 70; (c) 133; (d) 241