Adam has a total of 8 chickens and donkeys.
The difference in their number of legs is 4.
How many (a) donkeys and (b) chickens does Adam have?
Number of
chickens |
Number of
chickens' legs |
Number of
donkeys |
Number of
donkeys' legs |
Difference in the
number of legs |
| 8 |
8 x 2 =
16 |
0 |
0 x 4 =
4 |
16 - 0 =
16 |
| 7 |
7 x 2 =
14 |
1 |
1 x 4 =
4 |
14 - 4 =
10 |
| 6 |
6 x 2 =
12 |
2 |
6 x 4 =
8 |
12 - 8 =
4 |
If all of the animals are chickens,
the number of legs needed
= 8 x 2
= 16
Total difference in the number of legs
= 16 - 4
= 12
Difference in the number of legs when 1 chicken is replaced by 1 donkey
= 16 - 10
= 6
Number of donkeys
= 12 ÷ 6
= 2 (a)
Number of chickens
= 8 - 2
= 6 (b)
Answer(s): (a) 2; (b) 6
