How many seminars are conducted between Z’s seminar in

Solution

A attends seminar in afternoon at last among his friends. Y conducts seminar in morning and pre-noon on Monday and Thursday respectively.  Z is first among his friends to conduct seminar in afternoon Y does not attend seminar in afternoon on Tuesday. (so, Y must attend seminar in afternoon on Wednesday) and only place left for conduct seminar is evening, he must attend seminar in evening on Tuesday. We can see that Y and Z have attended seminar in Morning and afternoon respectively. C has attended seminar in evening on Wednesday (So, only possibility is A attending seminar in evening on Monday) and therefore, C must attend seminar in pre noon (left over place) on Monday. Therefore, we can clearly see that only Z has not attended seminar in evening yet. Therefore, Z will attend seminar in evening on Thursday. And C will attend the seminar in morning (only possible place) on Thursday.