Adam has 14 ducks and pigs.
These animals have 42 feet in all.
How many (a) ducks and (b) pigs does Adam have?
| Number of ducks |
Number of ducks' legs |
Number of pigs |
Number of pigs' legs |
Total number of legs between
the ducks and the pigs |
| 14 |
14 x 2 =
28 |
0 |
0 x 4 =
0 |
28 + 0 =
28 |
| 13 |
13 x 2 =
26 |
1 |
1 x 4 =
4 |
26 + 4 =
30 |
| 7 |
7 x 2 =
14 |
14 |
14 x 4 =
56 |
14 + 56 =
42 |
If all of the animals are ducks,
the number of legs needed
= 14 x 2
= 28
Total number of extra legs
= 42 - 28
= 14
Difference in the number of legs between 1 pig and 1 duck
= 4 - 2
= 2
The number of extra legs belongs to the pigs.
Number of pigs
= 14 ÷ 2
= 7 (b)
Number of ducks
= 14 - 7
= 7 (a)
Answer(s): (a) 7; (b) 7
