There are 90 people,
of which 30 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 = 30
Number of adults = 1 u
Number of girls = 1 u + 40
Total number of people
= 30 + 1 u + 1 u + 40
= 1 u + 1 u + 30 + 40
= 2 u + 70
2 u + 70 = 90
2 u = 90 - 70
2 u = 20
1 u = 20 ÷ 2 = 10
Number of adults
= 1 u
= 10
(b)
Number of children
= 30 + 1 u + 40
= 30 + 10 + 40
= 80
(c)
Number of less adults than children
= 80 - 10
= 70
(d)
Number of more girls than boys
= 1 u + 40 - 30
= 10 + 40 - 30
= 20
Answer(s): (a) 10; (b) 80; (c) 70; (d) 20