There's probably some really easy way to do this question but I spent about an hour at study this evening trying to do this question but I couldn't get ny head around it.... and yes it is annoying me at this point lol

basically it reads...

there are 11 black socks in a drawer and n white socks... if the probability of picking 2 n socks is 1/12 what is the value for n.

Can anybody please help

Thanking you