Let P, Q, R, S and T be five statements such that: I. If P is true, then both Q and S are true. II. If R and…
Let P, Q, R, S and T be five statements such that:
I. If P is true, then both Q and S are true.
II. If R and S are true, then T is false.
Which of the following can be concluded?
1. If T is true, then at least one of P and R must be false.
2. If Q is true, then P is true.
Select the correct answer using the code given below:
1 only
2 only
Both 1 and 2
Neither 1 nor 2
Solution
Conclusion 1: Suppose T is true. From rule II, 'R and S true implies T false', so if T is true, not both R and S are true; hence R is false or S is false. If S is false, then by rule I (P implies Q and S), P cannot be true. Thus T true implies at least one of P and R is false. Conclusion 1 follows. Conclusion 2: Q being true does not imply P is true (the implication is one-directional). Conclusion 2 does not follow. Only conclusion 1.