In Russian the middle name is the patronymic. Thus, the middle initial is the first letter of the father’s first name. And, as in many languages, the first initial is the first letter of the first name.

Below are the names of a Russian family's names:
• A.N. Petrov
• B.M. Petrov
• G.K. Petrov
• K.M. Petrov
• K.T. Petrov
• M.M. Petrov
• M.N. Petrov
• N.M. Petrov
• N.K. Petrov
• N.T. Petrov
• T.M. Petrov

Draw the family tree of the Petrovs, given that every father has two sons, the patriarch of the family has four grandsons, and his sons have two grandsons each.

Prove that the solution is unique.

Source: Tanya Khovanovna (sans solution)

Paterfamilias: Maxim Mikhailovich 

His sons: 
Tomas Maximovich 
Nikolas Maximovich 

Their sons: 
Kanishka Tomasovich 
Norodom Tomasovich 
and  
Mbuzulu Nikolasovich 
Adnan Nikolasovich 

Kanishka's sons: 
Nogbad Kanishkovich 
Gothmog Kanishkovich 

Mbuzulu's sons: 
Brian Mbuzulovich 
Kiernan Mbuzulovich 

Method: TM, KT, and MT clearly go together. AN, BM, and GK are isolates - they have no offspring, so nothing can come below them. From the rules, there must be one childless grandson in each branch. NK and GK then fit automatically under KT. At this stage,  NM, AN and MN have to go together, leaving MM, BM, and KM. BM is an isolate so it goes at the bottom; KM follows automatically, leaving MM as head of the family. Nice problem.

Edited on January 16, 2016, 6:25 am

Posted by broll on 2016-01-15 09:47:37