Hi agian.... I have one of those hand shaking problems..it says: There are 14 couples. There is some shaking of hands. No one shakes hand of thier date. No one shakes hands more than once with any one person. A boy asks each person how many times they shook hands. Each person gave him a different answer. How many times did the boy's date shake hands?Now, i thought it well through and i got the idea that assuming that everyone shook hands, then the total number of hand shakings would be "26+25+24+...+13+13+12..+1+0". (I drew a little sketch ) I thought that since there are two 13's (i'm not 100% sure, but i'm pretty sure;)) then, the boy has to be one of those 13's. And the problem is kinda solved...but, the TOTAL number that everyone shakes hands is the same, that is 26....so, i guess it cant be solved this way...anyway, i'm a little confused...i guess there is another way to solve it, or maybe i shouldnt assume that everyone shakes hands. Thanks agian.