Adam has a total of 9 chickens and horses.
The difference in their number of legs is 6.
How many (a) horses and (b) chickens does Adam have?
Number of chickens |
Number of chickens' legs |
Number of horses |
Number of horses' 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 chickens,
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 chicken is replaced by 1 horse
= 18 - 12
= 6
Number of horses
= 12 ÷ 6
= 2 (a)
Number of chickens
= 9 - 2
= 7 (b)
Answer(s): (a) 2; (b) 7