Answer:
75582
Step-by-step explanation:
The order of the correct problems does not matter, so the number of ways 8 of 19 problems can be correct is the number of combinations of 19 things taken 8 at a time:
C(n, k) = n!/(k!(n-k)!)
C(19, 8) = 19!/(8!(11!)) = 75582
