Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 10 : 3.
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 |
10 x 7 |
3 x 7 |
7 x 10 |
8 x 10 |
70 u |
21 u |
70 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 7 = 70
Class A
Boys : Girls
10 : 3
(x7) 70 : 21
Class B
Boys : Girls
7 : 8
(x10) 70 : 80
Number of boys in Class A = 70 u
(b)
Number of girls in Class B = 80 u
(c)
Number of children in Class B
= 70 u + 80 u
= 150 u
(d)
Number of children in Class A
= 70 u + 21 u
= 91 u
Total number of children
= 150 u + 91 u
= 241 u
Answer(s): (a) 70; (b) 80; (c) 150; (d) 241