The total cost of producing item X is

[devang.lakhani]

Following is a DS question:

The total cost of producing item X is equal to the sum of item X's fixed cost and variable cost. If the variable cost of producing X decreased by 5% in January, by what percent did the total cost of producing item X change in January?

(1) The fixed cost of producing item X increased by 13% in January.

(2) Before the changes in January, the fixed cost of producing item X was 5 times the variable cost of producing item X.

While reading option 2, is it not safe to assume that the fixed cost did not change in January?

[supratims]

No. option 2) only says how much was the fixed cost as a ratio of variable cost before January.

Is the answer C ?

[devang.lakhani]

Yes, the answer is C. I assumed that since they have not mentioned anything abt the fixed cost it did not change and marked the answer as B...:(

[RonPurewal]

that's a dangerous assumption to make. if you make similar assumptions, you'll miss pretty much ALL data sufficiency word problems, because the whole point of such problems is for you to figure out what you know and what you don't know.

i posted on this at length here:
post27360.html#p27360

[Aksy]

Why cant we pick numbers to solve this question?

[pseizert]

After identifying that statement 1 and statement 2 were insufficient on their own, I checked the math quickly with FC (before Jan) =100; VC (before Jan) at 20. This allowed me to calculate % increases in Jan from statement 1 and statement 2 together to get a total % change.

[jnelson0612]

Why cant we pick numbers to solve this question?

You could, but then you'd have to adjust them as directed by the problem and statements. Did you try that? If so, please report back! :-)