Question

Nathan has two types of stamps:

Answer 1

A. He could use 5 of the 8¢ Stamps 
    He could use 10 of the 4¢  Stamps 

B. You can be sure that you have found all of the possible combinations because those are the only sets of those specific numbers that equals 40¢ 

C. If Nathan used 40¢ worth of stamps in postage, given that 40¢ is all that Nathan is willing to spend, he would have only used the 8¢ variety of the stamps he owns. You can explain this reasoning in the fact that 8 x 5 = 40 and he spends 40¢.