Answer:
Franco has 66 baseball cards.
Explanation:
This question can be solved by a system of equations.
I am going to say that:
x is the number of baseball cards that Franco has.
y is the number of baseball cards that Juan has.
Franco has 18 fewer baseball cards than Juan.
This means that:

Also:

Together they have 150 baseball cards.
This means that:

Since





Franco has 66 baseball cards.