There are 80 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 = 80
2 u = 80 - 60
2 u = 20
1 u = 20 ÷ 2 = 10
Number of adults
= 1 u
= 10
(b)
Number of children
= 20 + 1 u + 40
= 20 + 10 + 40
= 70
(c)
Number of less adults than children
= 70 - 10
= 60
(d)
Number of more girls than boys
= 1 u + 40 - 20
= 10 + 40 - 20
= 30
Answer(s): (a) 10; (b) 70; (c) 60; (d) 30