In order to determine the number of horses and geeses, construct a system of equations, as follow:
There are 37 animals. If y is the number of horses and x the number of geeses, then, you can write:
x + y = 37
Now, consider that each geese has two feet and each horse has four feet. Due to you count 102 feet, then you can write:
2x + 4y = 102
Then, the system of equations is:
x+ y = 37
2x+ 4y = 102
Solve the previous system as follow:
Multiply the first equation by -2, then sum the result to the second equation and solve for y:
-2(x+ y = 37)
-2x - 2y = -74
-2x - 2y = -74
2x+ 4y = 102
2y = 28
y = 28/2
y = 14
Replace the previous value of y into any of the equations of the system and solve for x:
x + 14 = 37
x = 34 - 14
x = 20
Hence, there are 14 horses and 20 geeses.