Question 252442
Given, seven white socks and four black socks are in a drawer. Total 11 socks.
Two are selected at random.
Number of ways of selection = 11C2 = 11*10/2 = 55
Out of 7 white socks 2 white socks can be selected in 7C2 ways.
Out of 4 black socks 2 black socks can be selected in 4C2 ways.
Total number of ways of selecting the same colour = 7C2+4C2 = 7*6/2 + 4*3/2
                                                            = 27
Probability of getting both socks of same colour = 27/55