Kent and Hannah invited some of their friends at
a dinner. Some friends arrived with their spouses while some arrived
alone. Each guest greeted with every of the two hosts and with each
other guest. When two men greeted each other there were handshaking.
When two women greeted each other there were kissing. The same was
true when a man and a woman greeted each other.
It is known 6 handshakes and 12 kisses have been done in total. Can
you say how many guests arrived at the dinner, how many of them were
in couples and how many of them were alone? Obviously, when two guests
arrived as a couple they didnít greet each other.