Adam has a total of 15 hens and pigs.
The number of hens' legs is 18 less than the pigs' legs.
How many (a) hens and (b) pigs does Adam have?
| Number of pigs |
Number of pigs' legs |
Number of hens |
Number of hens' legs |
Number of less
hens' legs than pigs' legs |
15
|
15 x 4 =
60 |
0 |
0 x 2 =
0 |
60 - 0 =
60 |
| 14 |
14 x 4 =
56 |
1 |
1 x 2 =
2 |
56 - 2 =
54 |
| 8 |
8 x 4 =
32 |
7 |
7 x 2 =
14 |
32 - 14 =
18 |
(a)
If Adam has 15 pigs,
the number of legs
= 15 x 4
= 60
If Adam has 14 pigs and 1 hen,
number of less hens' legs than pigs' legs
= 14 x 4 - 1 x 2
= 56 - 2
= 54
Decrease in the number of legs when 1 pig is replaced by a 1 hen
= 60 - 54
= 6
Total decrease in the number of legs
= 60 - 18
= 42
Number of hens
= 42 ÷ 6
= 7
(b)
Number of pigs
= 15 - 7
= 8
Answer(s): (a) 7; (b) 8
