There are 100 people,
of which 20 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 = 20
Number of adults = 1 u
Number of girls = 1 u + 70
Total number of people
= 20 + 1 u + 1 u + 70
= 1 u + 1 u + 20 + 70
= 2 u + 90
2 u + 90 = 100
2 u = 100 - 90
2 u = 10
1 u = 10 ÷ 2 = 5
Number of adults
= 1 u
= 5
(b)
Number of children
= 20 + 1 u + 70
= 20 + 5 + 70
= 95
(c)
Number of less adults than children
= 95 - 5
= 90
(d)
Number of more girls than boys
= 1 u + 70 - 20
= 5 + 70 - 20
= 55
Answer(s): (a) 5; (b) 95; (c) 90; (d) 55