Question 1100933
As an incentive to do homework, Professor Rouse randomly draws three students' names, and they are expected to explain a homework problem of the day. On a particular day, 8 students have not done homework and 17 have. Find the following probabilities. 
(a) The first two drawn have not done homework and the third has.
Ans: [8C2/25C2][17/25] = (28/300)(17/25) = 0.0635
(b) All three drawn have not done homework.
Ans:: 8C3/25C3 
(c) All three drawn have done homework.
Ans: 17C3/25C3
(d) At least one of the three drawn has done homework.
Ans:: 1-[8C3/25C3]
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Cheers,
Stan H.
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