There are 810 people,
of which 90 are boys.
There are 400 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 = 90
Number of adults = 1 u
Number of girls = 1 u + 400
Total number of people
= 90 + 1 u + 1 u + 400
= 1 u + 1 u + 90 + 400
= 2 u + 490
2 u + 490 = 810
2 u = 810 - 490
2 u = 320
1 u = 320 ÷ 2 = 160
Number of adults
= 1 u
= 160
(b)
Number of children
= 90 + 1 u + 400
= 90 + 160 + 400
= 650
(c)
Number of less adults than children
= 650 - 160
= 490
(d)
Number of more girls than boys
= 1 u + 400 - 90
= 160 + 400 - 90
= 470
Answer(s): (a) 160; (b) 650; (c) 490; (d) 470