Answer
16
Work Step by Step
We are given two propositional variables p and q.
A truth table containing 2 propositional variables had 2 X 2=4 rows as each propositional variable has two possible truth values (true T or false F).
Now, we obtain different truth table if atleast one of the rows for different compound propositions differ in truth table.
Since there are 4 rows and each row has two possible truth values (true T or false F).
Thus there are 2 X 2 X 2 X 2=16 possible truth tables.