Fill in the blanks.
The ratio of the number of boys to the number of girls in Class A is 5 : 4.
The ratio of the number of boys to the number of girls in Class B is 7 : 9.
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 |
5 x 7 |
4 x 7 |
7 x 5 |
9 x 5 |
35 u |
28 u |
35 u |
45 u |
(a)
Change ratio into units.
The number of boys in Class A and Class B is the same.
LCM of 5 and 7 = 35
Class A
Boys : Girls
5 : 4
(x7) 35 : 28
Class B
Boys : Girls
7 : 9
(x5) 35 : 45
Number of boys in Class A = 35 u
(b)
Number of girls in Class B = 45 u
(c)
Number of children in Class B
= 35 u + 45 u
= 80 u
(d)
Number of children in Class A
= 35 u + 28 u
= 63 u
Total number of children
= 80 u + 63 u
= 143 u
Answer(s): (a) 35; (b) 45; (c) 80; (d) 143