January 2015

Oh no! Enough handshaking


I promise this is the last handshake problem I will pose for a long time to come. I couldn't help it. Found this problem while searching for good brain teasers and could not avoid the temptation of carrying it here (I admit all the brain teasers in Youthaffairz are borrowed from here, there and everywhere. Good questions need to be appreciated, and they can be appreciated only if they are widely circulated. But I assure you that the answers are my own - the reason why they are likely to be wrong every time).

This is the third "handshake" problem in Youthaffairz, and my apologies once again. Here is the question:

Prakash and his wife have been invited to a party. The party is attended by five other couples. Thus, there are six couples in all. This means there are twelve people - six men and six women.

When people meet, they shake hands or greet one another in other ways. At this party, too, the people chose to shake hands or join their hands in a "namaste". Of course, there was no need for a husband to shake hands with his wife, or a wife to shake hands with her husband. And, besides, one cannot shake his or her own hands.

After the greeting session was over, a curious Prakash wanted to know with how many people had each person shaken hands. So, he asked each person (including his wife) how many people they had shaken hands with. The question was, thus, addressed to eleven persons and Prakash received eleven different answers.

Is it possible to determine how many people had Prakash's wife shaken hands with?

Let me highlight the salient points of the question once again:

1. When Prakash asked the question, he received eleven different answers (no two persons gave the same answer).

2. There were no husband-wife handshakes.

The question is: How many people did Prakash's wife shake hands with?

Click here for the solution

Some useful links for
your career:

  • Union Public Service Commission - www.upsc.gov.in
  • IIT-Kharagpur - www.iitkgp.ac.in
  • Indian Statistical Institute - www.isical.ac.in
  • Indian Institute of Technology Madras - www.iitm.ac.in
  • Indian Institute of Management, Ahmedabad - www.iimahd.ernet.in
  • Indian Institute of Mass Commission - www.iimc.nic.in
  • IIT Bombay - www.iitb.ac.in
  • Indian School of Mines, Dhanbad - www.ismdhanbad.ac.in
  • Birla Institute of Technology, Ranchi - www.bitmesra.ac.in
  • Central Institute of Fisheries Nautical and Engineering Training - www.cifnet.nic.in
  • Indian Institute of Information Technology, Allahabad (Deemed University) - www.iiita.ac.in
  • Central Marine Fisheries Research Institute, Kochi - www.cmfri.com
  • Tata Institute of Social Sciences, Mumbai - www.tiss.edu

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