On a street with 50 houses, three students with paper routes deliver 28 Toronto Stars, 24 Globe and Mails, and 20 Toronto Suns. A house may receive no papers, one paper or two papers. (No houses receive all three.) No house, of course, receives more than one copy of the same newspaper. What is the least number houses that could have two papers delivered? Halivered? what is the greatest number of houses that could have two papers