Explanation

Phrased algebraically in terms of the quantities already given to us, the question is asking us for we'll be able to obtain this if we learn the values of both variables, or, otherwise, if we learn the value of an expression that fortuitously sheds light on the expression we want to solve for. Knowing that, we can head to the data statements, evaluating them separately first, as always.

Statement (1) tells us the difference between M and P, which is a component of what we are going for, but it's insufficient. Insofar as we are not completely certain of this fact by looking at the algebra, we can confirm it easily enough by examining cases. For example, M could be $20,000 and P could be $10,000, and then we'd be talking about a 100% increase. But another case would be to bump up each of those prices by $10,000, and then we'd be talking about a 50% increase. Both cases are allowed by the data given and they yield different answers, so we have insufficient information. Statement (1) alone is insufficient.

Statement (2) looks good. Recall that what we want to obtain is , which we can get if we determine . That expression is the same as , and in fact some people prefer to use that form of the expression when calculating percent change. So finding is completely sufficient to get the answer, and since , we have . The information is sufficient given the second statement alone.

The correct answer is (B).