Final answer:
There are 24 ways the four friends can finish the race.
Step-by-step explanation:
To determine the number of ways the four friends can finish the race, we need to use the concept of permutations. In permutations, the order of the objects matters. Since there are 4 friends running, there are 4 positions in the race and each position can be filled by any of the 4 friends. Therefore, the number of ways the four friends can finish the race is 4 x 3 x 2 x 1 = 24.