Answer:
Mistake in question, if there were 25 heads, then there are
13 chickens, 5 cows, 7 horses
Explanation:
System of Equations
Let's call x=number of chickens, y=number of cows, z=number of horses
We know Jack has two more horses than cows, so
z=y+2
We also know there are 24 heads, one per animal, so
x+y+z=24
Combining with the previous condition:
x+y+y+2=24
x+2y=22
We finally know there are 74 feet, two for each chicken and four for each cow or horse:
2x+4y+4z=74
Combining with the first condition
2x+4y+4(y+2)=74
2x+4y+4y+8=74
2x+8y=66
Dividing by 2
x+4y=33
Let's bring the first equation here
x+2y=22
Subtracting both
2y=11
It would give us a decimal number of cows
y=5.5
And a decimal number of horses
z=7.5
And a integer number of chickens
x=22-11=11
If the number of heads would have been 25, our problem will be correctly stated and the answer would be
13 chickens, 5 cows, 7 horses