Question 1118585
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#10 From a shipment of 65 transistors, 3 of which are defective, a sample of 4 transistors is selected at random.


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(a)  In how many different ways can the sample be selected?
  
     In {{{C[65]^4}}} = {{{(65*64*63*62)/(1*2*3*4)}}} = 788040 ways.



(b)  How many samples contain exactly 3 defective transistors?
  
     62 samples:  To the subset of 3 defective samples,  you can add ONE and ONLY ONE of the remaining 62 transistors.



(c)  How many samples do not contain any defective transistors?

     {{{C[62]^4}}} = {{{(62*61*60*59)/(1*2*3*4)}}} = 557845 samples.
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