SOLUTION: If we randomly select 2 diskettes, one after the other , from a box containing a diskettes of which 3 are unformatted, a. What is the probability that both of them will be unfo

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Question 634787: If we randomly select 2 diskettes, one after the other , from a box containing a diskettes of which 3 are unformatted,
a. What is the probability that both of them will be unformatted?
b. What is the probability that both of them will be formatted?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

box containing highlight%28a%29 diskettes  of which 3 are unformatted,

randomly select 2 diskettes, one after the other 

with replacement:

P (both unformatted) = %283%2Fa%29%283%2Fa%29

P (both formatted) = %28%28a-3%29%2Fa%29%28%28a-3%29%2Fa%29

without replacement:

P (both unformatted) = %283%2Fa%29%282%2F%28a-1%29%29

P (both formatted) = %28%28a-3%29%2Fa%29%28%28a-4%29%2F%28a-1%29%29