Roberto wants to display his 18 cards in an album. Some pages hold 2 cards and others hold 3 cards. How many different ways can roberto display his figure? What is the problem sentence to this question.

6 pages of 3; 4 pages of 3 and 3 pages of 2; 2 pages of 3 and 6 pages of 2; 9 pages of 2.  There are 4 ways to display his cards.  The problem sentence is 18=2x+3y