In a school, there is a total of 280 people.
10% are adults.
The rest are children.
The number of boys and girls is in the ratio of 2 : 7.
- What percentage of the people are boys?
- How many girls are there?
Adults |
Children |
Total |
1 u |
9 u |
10 u |
|
Boys |
Girls |
|
1 u |
2 u |
7 u |
10 u |
(a)
10% =
10100 =
110 The number of children is the combined repeated identity.
Adults : Children
1 : 10 - 1
1 : 9
Percentage of the people that are boys
=
210 x 100%
= 20%
(b)
Total number of people = 10 u
10 u = 280
1 u = 280 ÷ 10 = 28
Number of girls
= 7 u
= 7 x 28
= 196
Answer(s): (a) 20%; (b) 196