In a school, there is a total of 850 people.
40% are adults.
The rest are children.
The number of boys and girls is in the ratio of 3 : 7.
- What percentage of the people are boys?
- How many girls are there?
Adults |
Children |
Total |
2x10 |
3x10 |
5x10 |
|
Boys |
Girls |
|
|
3x3 |
7x3 |
|
20 u |
9 u |
21 u |
50 u |
(a)
40% =
40100 =
25 Adults : Children
2 : 5 - 2
2 : 3
Boys : Girls : Children
3 : 7 : 10
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 3 and 10.
LCM of 3 and 10 = 30
Percentage of the people that are boys
=
950 x 100%
= 18%
(b)
Total number of people = 50 u
50 u = 850
1 u = 850 ÷ 50 = 17
Number of girls
= 21 u
= 21 x 17
= 357
Answer(s): (a) 18%; (b) 357