Answer:
2730 ways.
Explanation:
There are 3 positions to be filled by the 15 runners.
For 1st place, we can fill this position in 15 ways.
After filling 1st place remaining runners = 14
Number 2 place can be filled by remaining 14 runners.
So, the 2nd place can be filled by 14 ways.
Again, after filling 2nd place remaining runners are 13.
Therefore, 3rd place can be filled by 13 ways.
Total number of ways to fill all three places = 15 × 14 × 13
= 2730 ways