<PRE><B>Question 1083927</B>
With replacement, the probability of 
0 defective is (4/5)^5=0.328
1 defective is 5(4/5)^4(1/5)
2 defective is 10(4/5)^3(1/5)^2
3 defective is 10(4/5)^2(1/5)^3
4 defective is 5(4/5)(1/5)^4
5 defective is (1/5)^5
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without replacement 
0 defective is (20/25)(19)24)(18/23)(17/22)(16/21) or 20C5/25C5=20!/15!5! divided by 25!/20!5!=0.2918
1 defective is 20C4*5C1/25C5
2 defective is 20C3*5C2/25C5
3 defective is 20C2*5C3/25C5
4 defective is 20C1*5C4/25C5
5 defective is 1/25C5=5/25*4/24*3/23*2/22*1/21=5C5/25C5=1/25!/5!20!=5!20!/25!=the first part.

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