In a school, there is a total of 2200 people.
10% are adults.
The rest are children.
The number of boys and girls is in the ratio of 1 : 9.
- What percentage of the people are boys?
- How many girls are there?
Adults |
Children |
Total |
1x10 |
9x10 |
10x10 |
|
Boys |
Girls |
|
|
1x9 |
9x9 |
|
10 u |
9 u |
81 u |
100 u |
(a)
10% =
10100 =
110 Adults : Children
1 : 10 - 1
1 : 9
Boys : Girls : Children
1 : 9 : 10
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 9 and 10.
LCM of 9 and 10 = 90
Percentage of the people that are boys
=
9100 x 100%
= 9%
(b)
Total number of people = 100 u
100 u = 2200
1 u = 2200 ÷ 100 = 22
Number of girls
= 81 u
= 81 x 22
= 1782
Answer(s): (a) 9%; (b) 1782