Is a positive?Statement 1: a - b > 0Statement 2: 2a - b > 0a)Sta...
Step 1: Decode the Question Stem
Q1. What kind of an answer will the question fetch?
The question is an "IS" question. For "is" questions, the answer is "YES" or "NO".
Step 2: Evaluate Statement 1 ALONE
Statement 1: a - b > 0.
From this statement we can conclude that a > b. But we cannot gain any insight about whether 'a' is positive.
Here are two possible scenarios where the statement is true without helping us arrive at any conclusion.
Example: Both 'a' and 'b' could be negative and 'a' could be greater than 'b'.
For example, a = -5 and b = -10. a - b > 0. 'a' is negative.
Counter Example: Alternatively 'a' could be positive.
For example, a = 10 and b could be 3. a - b > 0 and 'a' is positive.
A counter example exists.
Statement 1 alone is NOT sufficient.
Eliminate answer options A and D.
Step 3: Evaluate Statement 2 ALONE
Statement 2: 2a - b > 0.
From this statement we can conclude that 2a > b. However, we cannot gain any insight about whether 'a' is positive.
Let us check out the following two scenarios.
Example: Let a = -3, b = -100, 2a = -6. 2a > b and 'a' is negative.
Counter Example: Let a = 10, b = 12. Therefore, 2a = 20. 2a > b and a is positive.
A counter example exists.
Statement 2 ALONE is NOT sufficient.
Eliminate option B. Choices narrow down to C or E.
Step 4: Evaluate statements together
Statement 1: a - b > 0.
Statement 2: 2a - b > 0.
Let us look at the following two examples.
Example: a = -3, b = -100 and 2a = -6. a > b and 2a > b. 'a' is negative.
Counter Example: a = 20, b = 15 and 2a = 40. a > b and 2a > b. However, 'a' is positive.
A counter example exists.
Even after combining the information in the two statements, we cannot conclude whether 'a' is positive.
Statements together are not sufficient.
Eliminate answer option C.
Choice E is the correct answer.