In a school, there is a total of 580 people.
10% are adults.
The rest are children.
The number of girls and boys is in the ratio of 1 : 5.
- What percentage of the people are girls?
- How many boys are there?
Adults |
Children |
Total |
1x2 |
9x2 |
10x2 |
|
Girls |
Boys |
|
|
1x3 |
5x3 |
|
2 u |
3 u |
15 u |
20 u |
(a)
10% =
10100 =
110 Adults : Children
1 : 10 - 1
1 : 9
Girls : Boys : Children
1 : 5 : 6
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 9 and 6.
LCM of 9 and 6 = 18
Percentage of the people that are girls
=
320 x 100%
= 15%
(b)
Total number of people = 20 u
20 u = 580
1 u = 580 ÷ 20 = 29
Number of boys
= 15 u
= 15 x 29
= 435
Answer(s): (a) 15%; (b) 435