In: Statistics and Probability
Work the following probability sock problem, keeping in mind that this is a problem without replacement. When you take out a sock, it stays out.
Sock Problem:
Your sock drawer is very unorganized. No socks are paired, and they are all just thrown randomly into the drawer. You do know that the drawer has four red socks and four blue socks in it. You want to get some socks to wear in the morning, but you do not want to turn on a light for fear of waking up your family.
GIVEN THAT :-
According to the question we have that
drawer containing of 4 red socks and 4 blue socks
now finding out the following questions asked
FIND OUT :- If you draw two, what is the probability of a red pair match?
NOW solving
P(red pair match)=4C2/8C2
=6/28
=0.214
choose 2 out of 4 socks to get a red pair(4C2)
Total ways are to choose 2 socks out of 8 socks (8C2)
TO FIND :- If you draw two, what is the probability of a match of any color ?
as we done in the above methoed do it similarly
P(any pair match) = 4C2+4C2/8C2
=6+6/28
=0.428
TO FIND :- If you draw three, what is the probability of a match of any color?
FOR three to match we ca take any colour so
Total ways=8C3
there are four cases in selecting
P(All three are red)
P( all three are blue)
P( 1 red,2 blue)
P( 2 red, 1 blue)
so by doing the sum we get
P(All three are red) + P( all three are blue) + P( 1 red,2 blue) +P( 2 red, 1 blue).
=4C3+4C3+4C1*4C2+4C1*4C2
required probability=4+4+4*6+4*6/56
=56/56
=1
as we have in a pair only two socks . we cant chosse three .
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