There are twice as many children as adults in a bird park. There are 122 more boys than girls. If there are 378 people in the bird park,
- how many children are there?
- how many girls are there?
- how many boys are there?
| Children |
Adults |
Total |
| 2 u |
1 u |
3 u |
| Girls |
Boys |
|
|
| 1 p |
1 p + 122 |
|
|
(a)
Number of adults = 1 u
Number of children = 2 x 1 u = 2 u
Total number of people
= 2 u + 1 u
= 3 u
3 u = 378
1 u = 378 ÷ 3 = 126
(a)
Number of children
= 2 u
= 2 x 126
= 252
(b)
Number of girls = 1 p
Number of boys = 1 p + 122
1 p + 1 p + 122 = 252
2 p + 122 = 252
2 p = 252 - 122
2 p = 130
1 p = 130 ÷ 2 = 65
Number of girls
= 1 p
= 65
(c)
Number of boys
= 1 p + 122
= 65 + 122
= 187
Answer(s): (a) 252; (b) 65; (c) 187
