There are 100 people,
of which 10 are boys.
There are 70 less adults than girls.
- How many adults are there?
- How many children are there?
- How many less adults than children are there?
- How many more girls than boys are there?
(a)
Number of boys = 10
Number of adults = 1 u
Number of girls = 1 u + 70
Total number of people
= 10 + 1 u + 1 u + 70
= 1 u + 1 u + 10 + 70
= 2 u + 80
2 u + 80 = 100
2 u = 100 - 80
2 u = 20
1 u = 20 ÷ 2 = 10
Number of adults
= 1 u
= 10
(b)
Number of children
= 10 + 1 u + 70
= 10 + 10 + 70
= 90
(c)
Number of less adults than children
= 90 - 10
= 80
(d)
Number of more girls than boys
= 1 u + 70 - 10
= 10 + 70 - 10
= 70
Answer(s): (a) 10; (b) 90; (c) 80; (d) 70