Question 252282
a) 
1/3 * .15 = .05 
1/4 * .08 = .02
1/4 * .05 = .0125
1/6 * .01 = .0167
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=========>.08417
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1-.08417=.91583 prob 1 random product is a good one.
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b)
Let g=.91583 and d=.08417
(g+d)^7
nCr = n!/((n-r)r!) to find the coefficient of (g^5d^2)
7C2=21
21*.91583^5*.08417^2=.09585 prob that 2 out of 7 randomly selected will be defective.
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Ed