jmann@ihuxo.UUCP (08/24/83)
Following should clarify to the people who still think the probability of getting a gold coin after the first gold coin is 1/2 and not 2/3. Consider this figure: | C1 | C2 | C3 | | | | | ---------------------- | G | G | S | ---------------------- | G | S | S | ---------------------- | | | | The above picture has three cabinets C1, C2 and C3. Each of the cabinet has two drawers containing a silver(S) or a gold(G) coin. When the first opened drawer, top or bottom, has a god coin, it is clear that we have one of the three drawers containing a gold coin. For two of these three drawers the other drawer in the same cabinet will have a gold coin. Hence the probability is 2/3. The tricky part is to consider both the upper and lower drawers.