Answer:
a) 6 prizes
b) 1/1000; 3/2000; 997/1000
c) 15,75 € (I suppose)
Explanation:
a) 1+2+3=6
b) 2/2000 (2 of of the 2000), 3/2000, 1994/2000
c) (20×2000 - 5000 - 2×1000 - 3×500)÷2000
(total value of the tickets - total prizes value) ÷ number of the tickets