1. The problem statement, all variables and given/known data This is in fact an example with solutions. but I don't understand the solutions. So I am here to ask for explanation. Details are; In a city there are equal number of gentleman and ladies. 10% of gentleman are regarded as "good-looking" while 10% of ladies regarded as "good-looking". People form couples randomly. Given that a member of a couple is good-looking, find the probability that the other member is also good-looking 2. Relevant equations They first define G: set of good looking gentleman L: set of good looking ladies then i start to confuse here.......... P(the other is good-looking AND a member is good-looking) = P((L and G)and(L Union G)) = P(L and G) .......... P(a member is good looking) =P(L Union G) =....... 3. The attempt at a solution the solution and the problem is an example of conditional probability stated in the materials but... i just don't understand In my opinion, since the first member of a couple is GIVEN to be good-looking while people form couple randomly, then it should mean that a good looking member will not have a higher or less chance of finding a good-looking member to form couple. Then why it is a conditional probability?