Suppose that each of the 5 persons knows a piece of information, each piece is different, about a certain event. Each time person A calls person B, A gives B all the information that A knows at that moment about the event, while B does not say to A anything that he knew.
(a) What is the minimum number of calls are necessary so that everyone knows about the event?
(b) How many calls are necessary if there were n persons? geometrygeometric transformationcombinatorics proposedcombinatorics