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Puzzle #26: Probability of picking 2 Socks of Same colour | Infosys | Amazon



There are 6 pairs of black socks and 6 pairs of white socks. What is the probability to pick a pair of black or white socks when 2 socks are selected randomly in darkness?



Puzzle Solution:

Ways to pick any 2 socks from 24 socks = 24C2

Ways to pick 2 BLACK socks from 12 BLACK socks = 12C2


Probability of picking 2 BLACK socks (P1)= 12C2 / 24C2 = 66/276

Probability of picking 2 WHITE socks (P2)= 12C2 / 24C2 = 66/276


Probability of picking any 2 same color socks = P1+P2 = 66/276 + 66/276 = 11/23


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