Answer: The number of different ways can Roberto display his figure =4
Explanation:
As per given , we have
Total cards = 18
Let 'a' be the number of pages with 2 cards and 'b' be the number of pages with 3 cards.
such that
(i)
Now , we need to find the possible solutions for (a,b) , where a, b are positive integers and satisfy equation (i).
When a=0 ,

When b=0 ,

When a=3 ,

When a=6 ,

i.e. Possible solutions for (a,b) = (0,6), (9,0) , (3,4) , (6,2) .
⇒Number of possible solutions for (a,b) =4
Thus , the number of different ways can Roberto display his figure =4