Read the given data first! This could be very tricky one. Let's assume that the Matt is fifth fastest and fifth slowest runner in his school.
Then there are 4 runners ahead of him numbered 1 to 4 and 4 behind him numbered 6 to 9. So there would be total 9 runners in his school in the case.
But Matt is 50th fastest runner meaning 49 are ahead of him numbered 1 to 49. And 49 are behind him numbered as 51 to 99 (total 49) while Matt is at 50th position.
Hence, there are 49 + 1 + 49 = 99 runners in his school.
