Socks in the Drawer
A drawer contains a number of red and blue socks. If I pull two out at random, then the chances of them being a red pair is and the chance of them being a blue pair is . How many socks are in the drawer ?
The answer is 120.
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1 solution
Consider x=number of red socks, y= number of blue socks Pulling 2 consecutive red socks : x/(x+y) * (x-1)/(x+y-1)=1/2 Pulling 2 consecutive blue socks: y/(x+y)*(y-1)/(x+y-1)=1/12 Solve this
x= 85,y=35