To solve this problem, I drew a graph shown below and tried to solve the problem using the graph. I found it very complicated, so I don't believe that I am on right track. What is the easy way to solve the problem? (I try to include the graph, but the system does not allow me to do so because I am new here.)

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> In a small town of 100 men, 85 are married, 70 have a telephone, 75 own a car, and 80 own their own home. On this basis, what is the least possible number of men who are married, have their own telephone, own their own car, and own their own house? 
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