Answer:
He have 47 ducks and 7 cows.
Explanation:
Given:
Farmer Jones raises ducks and cows.
He looks out his window and sees 54 animals with a total of 122 feet.
Now, to find the each type of animal he have.
Let the number of ducks be

And the number of cows be

So, total number of animals are:

....( 1 )
As, the feet of cows are 4 and ducks are 2.
Now, the total number of feet are:


Substituting the value of
from equation (1) we get:



Subtracting both sides by 108 we get:

Dividing both sides by 2 we get:

The number of cows = 7.
Now, to get the number of ducks we substitute the value of
in equation (1):

The number of ducks = 47.
Therefore, he have 47 ducks and 7 cows.