Data Sufficiency

a, b and c are positive numbers. Is a>b-c?

1) a, b, and c are the lengths of three different sides of a triangle
2) a^2+b^2=c^2

=>

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

The first step of the VA (Variable Approach) method is to modify the original condition and the question. We then recheck the question. We should simplify conditions if necessary.

Condition 1)
If a, b and c are the lengths of the three sides of a triangle, we must have
a > b - c since the length of each side of a triangle is always greater than the difference between the lengths of the other two sides. Thus, condition 1) is sufficient.

Condition 2)
We can assume a, b and c are the sides of a right triangle. The above reasoning tells us that a > b - c. Thus, condition 2) is also sufficient.

Therefore, D is the answer.
Answer: D

Note: Tip 1) of the VA method states that D is most likely to be the answer if condition 1) gives the same information as condition 2).