There are 100 people,
of which 20 are boys.
There are 50 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 + 50
Total number of people
= 20 + 1 u + 1 u + 50
= 1 u + 1 u + 20 + 50
= 2 u + 70
2 u + 70 = 100
2 u = 100 - 70
2 u = 30
1 u = 30 ÷ 2 = 15
Number of adults
= 1 u
= 15
(b)
Number of children
= 20 + 1 u + 50
= 20 + 15 + 50
= 85
(c)
Number of less adults than children
= 85 - 15
= 70
(d)
Number of more girls than boys
= 1 u + 50 - 20
= 15 + 50 - 20
= 45
Answer(s): (a) 15; (b) 85; (c) 70; (d) 45