Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
Both Betty and Wilma earn annual salaries of more than $50000. Is Wilma's annual salary greater than Betty's?
(1) Betty's annual salary is closer to $50,000 than is Wilma's.
(2) Betty's annual salary is closer to $35,000 than it is to Wilma's annual salary.
In the original condition, we can let Betty's annual salary=b, Wilma's annual salary=w. Then, there are 2 variables and 3 equations from the question and the conditions, so there is high chance (D) will be our answer.
Condition 1 is sufficient as it answers the question 'yes'
Condition 2 is also sufficient for the same reason, so the answer becomes (D).
For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.