There are 100 people,
of which 20 are boys.
There are 40 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 = 20
Number of adults = 1 u
Number of girls = 1 u + 40
Total number of people
= 20 + 1 u + 1 u + 40
= 1 u + 1 u + 20 + 40
= 2 u + 60
2 u + 60 = 100
2 u = 100 - 60
2 u = 40
1 u = 40 ÷ 2 = 20
Number of adults
= 1 u
= 20
(b)
Number of children
= 20 + 1 u + 40
= 20 + 20 + 40
= 80
(c)
Number of less adults than children
= 80 - 20
= 60
(d)
Number of more girls than boys
= 1 u + 40 - 20
= 20 + 40 - 20
= 40
Answer(s): (a) 20; (b) 80; (c) 60; (d) 40