UPSC CSE Prelims 2015
The selection of a host is done by picking lots once a month. This method implies a random and independent selection process for each of the twelve months in a year. Consequently, for any specific member, the probability of being chosen remains constant each month. There is no mechanism described that ensures a member hosts a fixed number of times, or that prevents them from hosting multiple times, or not at all. Therefore, the exact number of dinners a particular member will host in one year cannot be deterministically predicted from the given information.
Option 1 (One): This option suggests a fixed rotation or a guarantee that each member hosts exactly once per year. However, the problem states selection by "picking lots," which indicates a random process. A random selection does not guarantee that each member will host precisely once in a year, as a member could be chosen more than once or not at all.
Option 2 (Zero): While it is possible for a particular member to host zero dinners in a year (if they are never selected by lot), this is not a guaranteed or predictable outcome for any specific member. The question asks for "the number of dinners a particular member has to host," implying a definite value, which "zero" is not in this context.
Option 3 (Three): This is an arbitrary number that lacks any basis in the problem statement. The mechanism of "picking lots" does not lead to a predictable outcome of three dinners for any particular member.