There are twice as many adults as children in a zoo, and there are twice as many boys as girls. If there are 1800 people in the zoo,
- how many adults are there?
- how many children are there?
- how many boys are there?
| Adults |
Children |
| |
Girls |
Boys |
| |
1 u |
2 u |
| 6 u |
3 u |
(a)
Number of girls = 1 u
Number of boys = 2 x 1 u = 2 u
Number of children = 2 u + 1 u = 3 u
Number of adults = 2 x 3 u = 6 u
People in the zoo
= 3 u + 6 u
= 9 u
9 u = 1800
1 u = 1800 ÷ 9 = 200
Number of adults
= 6 u
= 6 x 200
= 1200
(b)
Number of children
= 3 u
= 3 x 200
= 600
(c)
Number of boys
= 2 u
= 2 x 200
= 400
Answer(s): (a) 1200; (b) 600; (c) 400
