Question: there are birds and can be hit 75% of the time, however only the first
person can hit it 75% of the time, the second person can hit it 80% as well
as the first person. ( I think that means they can hit it 60% of the time).
If the two people shoot on arrow at 19 different birds what is the
probability that the first person will hit 10 birds and the second hit 4.

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i think its a hypergeometric problem, but i have trouble finding what needs
to be plugged into the equation

*HYPERGEOMETRIC (Sampling without replacement)*

Given: a = # of possible successes

b = # of possible failures

x = # actual successes

n = # trials or sample size

P(x) = {(aCx) x (b C n-x)} / (a+b C n)

Thanks!
  Edit

Answer: Here n = # of trials or sample size = 19
X = # actual success= 14
a = # of possible success = 75% of 19 + 80% of 9= 21.45 = 21
and b= # of possible failures = 25% of 19 + 20% of 9= 6.55= 7
a+b= 28
then P(x)= 0.3535 (ans.)  Edit