Answer:
43680 different arrangements are possible.
Explanation:
The total number of horses are :16
We have to find different arrangement of four horses
Since, we have to find arrangements means we will use permutation
So, the required arrangement will be:

Now, using:

Here, n= 16 and r=4 on substituting the values we get:



Cancel out the common term that is 12! we get:

After simplification we get: 43680
Hence, 43680 different arrangements are possible.