There are some cows, ducks and sheep in a farm.There are 5 times as many ducks as sheep. Jaslyn finds out that among the animals, there are a total of 29 heads and 76 legs. How many cows 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 |
29
|
29 x 4 =
116 |
0
|
0
|
116
|
28
|
28 x 4 =
112 |
1
|
1 x 2 =
2 |
114
|
9
|
9 x 4 =
36 |
20
|
20 x 2 =
40 |
40 |
Total number of legs if all are 4-legged animals
= 4 x 29
= 116
Big difference between all the 2-legged animals and all the 4-legged animals
= 116 - 76
= 40
Small difference between one 2-legged animal and one 4-legged animal
= 4 - 2
= 2
Number of ducks
= 40 ÷ 2
= 20
Number of 4-legged animals
= 29 - 20
= 9
Number of sheep = 1 u
Number of ducks = 5 u
5 u = 20
1 u = 20 ÷ 5 = 4
Number of sheep
= 1 u
= 4
Number of cows
= 9 - 4
= 5
Answer(s): 5
