Let’s follow through some of the analysis so far:

Statement 1

0+2 = 2? Yes
0-2 = 2? No
0/2 = 2? No
0*2 = 2? No

(1) is sufficient.

Statement 2

2+0 = 2?Yes
2-0 = 2?Yes

With (1) you DEFINITELY know * must be +. So Statement (1) is good.

With (2), it could be EITHER “+” or “-”. There is indeed ambiguity regarding which operation you should use.

But look carefully at the question. It asks:
what is the value of 1*0?

Well, let’s break it down with the two operations: addition and subtraction.

what is the value of 1+0?
What is the value of 1-0?

Notice the answer to each of the two situations is 1! There is NO ambiguity to the question.The answer is always 1 regardless of addition or subtraction.

Remember you need to answer the question and not get confused with the intermediary steps. When there is no ambiguity to the question then you know you do indeed have enough information. Therefore, (2) alone is good as well as (1) alone. So the overall answer is (D).

If I missed a point, please point out, but this seems like a typical way GMAT tries to trick you.

Let’s take a look.

There are three areas:
1) Beginning
2) Percentage change
3) End

The question asks what was the end balance—basically it’s like for item #3. This is a typical framework of the GMAT Pill. You basically need two of the 3 in order to find the 3rd piece.So in order to find the end balance, you need both the beginning balance and the percentage change in between.

With statement (1) you see a HYPOTHETICAL percentage change and you also see a HYPOTHETICAL end number. From this you have enough info to find the ACTUAL BEGINNING balance–that’s the first piece of info we need but not enough to find the end balance.

With statement (2) we are given the ACTUAL PERCENTAGE change–that’s exactly the second piece of info we need in order to find the ACTUAL END balance. By itself, (2) is not enough info, but as we already knew we needed 2 pieces of info to solve this question and statement (2) gave us that. Therefore, only when combining both statements do we have enough info.