SOLUTION: In a shipment of 50 transformers, 10 are known to be defective. If 30 transformers are picked at random, what is the probability that all 30 are nondefective? Assume that all trans

Algebra ->  Probability-and-statistics -> SOLUTION: In a shipment of 50 transformers, 10 are known to be defective. If 30 transformers are picked at random, what is the probability that all 30 are nondefective? Assume that all trans      Log On


   



Question 191547: In a shipment of 50 transformers, 10 are known to be defective. If 30 transformers are picked at random, what is the probability that all 30 are nondefective? Assume that all transformers look alike and have an equal probability of being chosen.
Answer by Edwin McCravy(20063) About Me  (Show Source):
You can put this solution on YOUR website!

There are 10 defective transformers and 40 non-defective 
transformers.

To be successful we have 40 from which to choose 30.
That can be done C(40,30) ways.  So that's the numerator
of the desired probability.

To be successful or unsuccessful we have 50 from which 
to choose 30. That can be done C(50,30) ways.  So that's the 
denominator of the desired probability.

So the desired probability is

C%2840%2C30%29%2FC%2850%2C30%29

.00001798588365

Edwin