Final answer:
To find the number of possible combinations of truth values in a truth table with 6 rows, use the formula 2^6, which equals 64. Therefore, the answer to how many possible combinations exist is 64.
Step-by-step explanation:
In a truth table with 6 rows, to determine how many possible combinations of truth values exist for the given propositions, you need to consider that there are two possible truth values for each proposition: true (T) and false (F). For each proposition, this binary choice gives us 2 possibilities. Since each row represents a unique combination of these truth values, when there are 6 rows, we use the formula 2 to the power of the number of propositions (n). Therefore, the total number of possible combinations is 2^6.
To calculate this, we take 2^n where n is the number of rows or propositions. So, we have 2^6 which is equal to 64 possible combinations. This means that the correct choice from the provided options is (b) 64.