Adam has a total of 9 hens and goats.
The difference in their number of legs is 6.
How many (a) goats and (b) hens does Adam have?
Number of
hens |
Number of
hens' legs |
Number of
goats |
Number of
goats' legs |
Difference in the
number of legs |
| 9 |
9 x 2 =
18 |
0 |
0 x 4 =
4 |
18 - 0 =
18 |
| 8 |
8 x 2 =
16 |
1 |
1 x 4 =
4 |
16 - 4 =
12 |
| 7 |
7 x 2 =
14 |
2 |
7 x 4 =
8 |
14 - 8 =
6 |
If all of the animals are hens,
the number of legs needed
= 9 x 2
= 18
Total difference in the number of legs
= 18 - 6
= 12
Difference in the number of legs when 1 hen is replaced by 1 goat
= 18 - 12
= 6
Number of goats
= 12 ÷ 6
= 2 (a)
Number of hens
= 9 - 2
= 7 (b)
Answer(s): (a) 2; (b) 7
