Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 10 : 7.
The ratio of the number of boys to the number of girls in Class B is 3 : 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 |
10 x 3 |
7 x 3 |
3 x 10 |
8 x 10 |
30 u |
21 u |
30 u |
80 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 10 and 3 = 30
Class A
Boys : Girls
10 : 7
(x3) 30 : 21
Class B
Boys : Girls
3 : 8
(x10) 30 : 80
Number of boys in Class A = 30 u
(b)
Number of girls in Class B = 80 u
(c)
Number of children in Class B
= 30 u + 80 u
= 110 u
(d)
Number of children in Class A
= 30 u + 21 u
= 51 u
Total number of children
= 110 u + 51 u
= 161 u
Answer(s): (a) 30; (b) 80; (c) 110; (d) 161