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Probability
A drawer contains a number of Red and Blue socks. If I pull two out of random, then the chance of
them being a Red pair is a half and chance of them being a blue pair is a twelfth. How many socks are
in the drawer?
Read Solution (Total 5)
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- i found out that the answer is 120..but dnt know how.
- 12 years agoHelpfull: Yes(2) No(12)
- 85 red, 35 blue"
- 9 years agoHelpfull: Yes(0) No(1)
- Can you all please explain it once.
How are you getting these numbers? - 9 years agoHelpfull: Yes(0) No(0)
- i got 140
2/14*140 only satisfy and give proper integer, but I don't know how - 7 years agoHelpfull: Yes(0) No(0)
- Let the number of red socks be x.
Let the number of blue socks be y.
Total number of socks =x+y
If two socks are pulled out, then
Probability that both of them is red =x(x+y).(x−1)(x+y−1)=12
Probability that both of them is blue =y(x+y).(y−1)(x+y−1)=112
On solving these two equations we get x(x−1)=6y(y−1).
Now we have to assume values of x and y such that the above statement is true.
Since,
85×84=6×35×34⇒85(85−1)=6×35(35−1)
So, there are 85 red socks and 35 blue socks.
Thus, there are 85+35=120 socks in the drawer. - 5 years agoHelpfull: Yes(0) No(0)
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