Good morning my dear pupils.
As you can see Professor Moriarty is also a trickster. He was probably scarce of funds!
The answer to this problem is easy, specially if you use your knowledge on divisibility. Some of you found it.
You have to look for a divisor of 3895 greater than 50 and smaller than 100. You can factorice he number 3895 = 5·19 · 41. Each factor is smaller than 50, so you must take the product of two of them. The only solution is 95 = 5 · 19.
Then the solution is 95 people, each one lost 41 pounds.