Stamps
Source: Canada 1974/6
January 13, 2007
Problem Statement
An unlimited supply of 8-cent and 15-cent stamps is available. Some amounts of postage cannot be made up exactly, e.g., 7 cents, 29 cents. What is the largest unattainable amount, i.e., the amount, say , of postage which is unattainable while all amounts larger than are attainable? (Justify your answer.)