Answer:
102080160 ways
Explanation:
There are a total of 42 people that participate in a race. We're looking for the top 5 finishers. Therefore, we will use permutation to pick five finishers and arrange them in positions.

"n" is the total which is 42, and "r" is the chosen, which is 5. Therefore, substitute in:

Therefore, 102080160 sequences for the top 5 finishers with 42 participants are possible.