There are some donkeys, hens and cows in a farm.There are 3 times as many hens as cows. Diana finds out that among the animals, there are a total of 28 heads and 82 legs. How many donkeys are there?
Number of
4-legged animals |
Total legs of
4-legged animals |
Number of
2-legged animals |
Total legs of
2-legged animals |
Total legs |
28
|
28 x 4 =
112 |
0
|
0
|
112
|
27
|
27 x 4 =
108 |
1
|
1 x 2 =
2 |
110
|
13
|
13 x 4 =
52 |
15
|
15 x 2 =
30 |
30 |
Total number of legs if all are 4-legged animals
= 4 x 28
= 112
Big difference between all the 2-legged animals and all the 4-legged animals
= 112 - 82
= 30
Small difference between one 2-legged animal and one 4-legged animal
= 4 - 2
= 2
Number of hens
= 30 ÷ 2
= 15
Number of 4-legged animals
= 28 - 15
= 13
Number of cows = 1 u
Number of hens = 3 u
3 u = 15
1 u = 15 ÷ 3 = 5
Number of cows
= 1 u
= 5
Number of donkeys
= 13 - 5
= 8
Answer(s): 8
