Adam has a total of 12 chicken and goats.
The number of chicken' legs is 18 less than the goats' legs.
How many (a) chicken and (b) goats does Adam have?
| Number of goats |
Number of goats' legs |
Number of chicken |
Number of chicken' legs |
Number of less
chicken' legs than goats' legs |
12
|
12 x 4 =
48 |
0 |
0 x 2 =
0 |
48 - 0 =
48 |
| 11 |
11 x 4 =
44 |
1 |
1 x 2 =
2 |
44 - 2 =
42 |
| 7 |
7 x 4 =
28 |
5 |
5 x 2 =
10 |
28 - 10 =
18 |
(a)
If Adam has 12 goats,
the number of legs
= 12 x 4
= 48
If Adam has 11 goats and 1 chicken,
number of less chicken' legs than goats' legs
= 11 x 4 - 1 x 2
= 44 - 2
= 42
Decrease in the number of legs when 1 goat is replaced by a 1 chicken
= 48 - 42
= 6
Total decrease in the number of legs
= 48 - 18
= 30
Number of chicken
= 30 ÷ 6
= 5
(b)
Number of goats
= 12 - 5
= 7
Answer(s): (a) 5; (b) 7
