There are some cows, chickens and buffaloes in a farm.There are 2 times as many chickens as buffaloes. Betty finds out that among the animals, there are a total of 31 heads and 100 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 |
31
|
31 x 4 =
124 |
0
|
0
|
124
|
30
|
30 x 4 =
120 |
1
|
1 x 2 =
2 |
122
|
19
|
19 x 4 =
76 |
12
|
12 x 2 =
24 |
24 |
Total number of legs if all are 4-legged animals
= 4 x 31
= 124
Big difference between all the 2-legged animals and all the 4-legged animals
= 124 - 100
= 24
Small difference between one 2-legged animal and one 4-legged animal
= 4 - 2
= 2
Number of chickens
= 24 ÷ 2
= 12
Number of 4-legged animals
= 31 - 12
= 19
Number of buffaloes = 1 u
Number of chickens = 2 u
2 u = 12
1 u = 12 ÷ 2 = 6
Number of buffaloes
= 1 u
= 6
Number of cows
= 19 - 6
= 13
Answer(s): 13
