The toughest thing about data sufficiency questions is the format. Luckily the answer choices never change. They are:
A Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D EACH statement ALONE is sufficient.
E Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data are needed.
The math itself is the same math tested in the Problem Solving section, but the actual questions are distilled into two types: “yes/no” and “value.” For “yes/no” questions, you only need enough information that will allow you to conclusively answer either yes or no. There is no “correct” answer. Our task is merely to determine when we have enough information.
For “value” questions, consider what information would be necessary to solve the problem. What pieces of information are missing? For example, to draw a line on a graph we might be missing information such as the y-intercept, the slope, or two points on the line.
Once you determine the type of question and have analyzed the information given, analyze the first two statements independently of each other. Try to “forget” statement 1 before you move on to statement 2. Don’t underestimate how challenging this can be!
Write out A through E on your scratch paper as you practice, and use the process of elimination to narrow down choices.
If 1 is sufficient, eliminate B, C, and E. The only two options are A and D.
Conversely if 1 is NOT sufficient, eliminate A and D.
Simply by appropriately analyzing the first statement, you can eliminate two or three answer choices! If statement 1 is challenging for you, you can start by analyzing statement 2. If statement 2 is insufficient, then choices B and D can immediately be eliminated. It doesn’t matter which statement you analyze first, as long as you start by looking at them individually.
If neither statement is sufficient on its own, then the options left are C and E. Try combining the statements to see if together they would provide enough information to arrive at an answer. If they don’t the answer is E.
Avoid calculating whenever possible. Data sufficiency questions are not supposed to involve long and drawn-out calculations. If you find yourself doing a lot of math, there is probably something you’re not seeing. Remember that variables can equal a variety of values: negatives, positives, integers, fractions, zero. Don’t simplify when you don’t know what a variable can equal, and don’t assume variables are positive integers!
Is c > 2 if a + b + c > 0 ?
(1) c > a + b + 2
(2) a + b + 2 < 0
This is a “yes/no” question. The question is asking if c is greater than 2. First let’s analyze the given information before looking at the answer choices. We are told that a + b + c > 0. If we isolate c, that gives us c > -(a + b). To answer this question, we need to determine the values of a and b.
If (a + b) = -2,
c > – (-2)
c > 2
Then the answer would be “yes.” What about if (a + b) was smaller or larger than -2?
If (a + b) = -1
c > – (-1)
c > 1
The answer would be “maybe” since there are numbers larger than 1 but smaller than 2.
What about if (a + b) was smaller than -2?
If (a + b) = -3
c > – (-3)
c > 3
The answer would be “yes” since all values greater than 3 are also greater than 2.
So we have determined that we need (a + b) to be a number less than -2. Let’s express that as an inequality.
a + b < -2
Now we can evaluate the statements. Statement 2 is equivalent to our inequality and is therefore sufficient. Notice how much work we did before reading the statements!

Is it financially viable?