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A lot of 40 spacing washers contains 30 washers that are thicker than the target dimension. Suppose that three washers are selected at random, without replacement, from the lot.

(a) What is the probability that all three washers are thicker than the target?

(b) What is the probability that the third washer selected is thicker than the target if the first two selected are thinner than the target?

(c) What is the probability that the third washer selected is thicker than the target?

 Feb 24, 2020

Best Answer 

 #1
avatar+23246 
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a)  Probability  =  (30/40) x (29/39) x (28/38)

 

b)  Probability  =  (10/40) x (9/39) x (30/38)

 

c)  If you know nothing about any of the other washers, the probability that the third washer is thicker is  30/40.

 Feb 24, 2020
 #1
avatar+23246 
+1
Best Answer

a)  Probability  =  (30/40) x (29/39) x (28/38)

 

b)  Probability  =  (10/40) x (9/39) x (30/38)

 

c)  If you know nothing about any of the other washers, the probability that the third washer is thicker is  30/40.

geno3141 Feb 24, 2020

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