When we evaluate statement (1), we can tell that there are 10 brown cars in the lot, because
that’s the only number that would give us a ratio of 2:3 if there are 15 blue cars. So we can eliminate
B, C, and E.
Taking statement (2) alone, we can tell that we have 15 blue and 10 brown cars in the lot, because
those are the only numbers that would add up to 25 and give a ratio of 2:3. So either statement is
sufficient on its own, which means D is the correct answer.