In a school, there is a total of 1550 people.
30% are adults.
The rest are children.
The number of boys and girls is in the ratio of 1 : 4.
- What percentage of the people are boys?
- How many girls are there?
Adults |
Children |
Total |
3x5 |
7x5 |
10x5 |
|
Boys |
Girls |
|
|
1x7 |
4x7 |
|
15 u |
7 u |
28 u |
50 u |
(a)
30% =
30100 =
310 Adults : Children
3 : 10 - 3
3 : 7
Boys : Girls : Children
1 : 4 : 5
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 7 and 5.
LCM of 7 and 5 = 35
Percentage of the people that are boys
=
750 x 100%
= 14%
(b)
Total number of people = 50 u
50 u = 1550
1 u = 1550 ÷ 50 = 31
Number of girls
= 28 u
= 28 x 31
= 868
Answer(s): (a) 14%; (b) 868