There are thrice as many children as adults in a bird park. There are 128 more boys than girls. If there are 760 people in the bird park,
- how many children are there?
- how many girls are there?
- how many boys are there?
| Children |
Adults |
Total |
| 3 u |
1 u |
4 u |
| Girls |
Boys |
|
|
| 1 p |
1 p + 128 |
|
|
(a)
Number of adults = 1 u
Number of children = 3 x 1 u = 3 u
Total number of people
= 3 u + 1 u
= 4 u
4 u = 760
1 u = 760 ÷ 4 = 190
(a)
Number of children
= 3 u
= 3 x 190
= 570
(b)
Number of girls = 1 p
Number of boys = 1 p + 128
1 p + 1 p + 128 = 570
2 p + 128 = 570
2 p = 570 - 128
2 p = 442
1 p = 442 ÷ 2 = 221
Number of girls
= 1 p
= 221
(c)
Number of boys
= 1 p + 128
= 221 + 128
= 349
Answer(s): (a) 570; (b) 221; (c) 349
