2006 AMC 10B Problems/Problem 22
Problem
Elmo makes 
sandwiches for a fundraiser. For each sandwich he uses 
globs of peanut butter at 
¢ per glob and 
blobs of jam at 
¢ per blob. The cost of the peanut butter and jam to make all the sandwiches is 
. Assume that , , and are positive integers with 
. What is the cost of the jam Elmo uses to make the sandwiches?
Solution
The peanut butter and jam for each sandwich costs 
¢, so the peanut butter and jam for sandwiches costs 
¢.
Setting this equal to 
¢:
The only possible positive integer pairs 
whose product is are: 
The first pair violates and the third and fourth pair have no positive integer solutions for and .
So, 
and 
The only integer solutions for and are 
and 
Therefore the cost of the jam Elmo uses to make the sandwiches is 
¢ 
1.65 \Rightarrow D $
