Correct Answer: A
Explanation:
Statement (1) says that a/b = 2. We are looking for the ratio 2a/b. If you substitute 2 for a/b in that ratio, you get 2 times 2, which equals 4. Statement (1) is sufficient. Cross off B, C, and E.
How about statement (2)? Remember, you have to forget about the information you got from
statement (1). Since there are several values for a and b that would add up to 5, let’s try a couple of variations to see if we always get the same ratio. If a is 3 and b is 2, the ratio of 2a to b would be 6:2 or 3:1. But if we used a = 2 and b = 3 instead (and nothing tells us that we can’t), the answer to the question stem becomes 4:3. When we can get different answers, we can tell the statement is not sufficient, so we can eliminate D. A is the correct answer.