1. The question below consists of two statements, S1 and S2. You have to decide whether the statements are sufficient to answer the question. A1. If the answer can be obtained from S1 alone, but not from S2 alone. A2. If the answer can be obtained from S2 alone, but not from S1 alone. A4. If S1 alone is sufficient and S2 alone is sufficient to obtain the answer. A5. If the answer cannot be obtained even after using both S1 and S2 together, and more information is required. What is the value of $a + b$? S1: $a + 2b = 7$ S2: $3a + b = 6$

2. The question below consists of two statements, S1 and S2. You have to decide whether the statements are sufficient to answer the question. A1. If the answer can be obtained from S1 alone, but not from S2 alone. A2. If the answer can be obtained from S2 alone, but not from S1 alone. A3. If the answer can be obtained from S1 and S2 together, although neither statement alone is sufficient. A4. If S1 alone is sufficient and S2 alone is sufficient to obtain the answer. Three points P, Q, and R lie on a straight line. Point R lies between P and Q. The distance between P and Q is 50 meters. What is the distance between Q and R? S1: Distance PR is $\frac{1}{3}$ of QR. S2: Distance PQ is $20%$ more than QR.