Official Guide Explanation:
Data Sufficiency #63

Background

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Solution and Metadata

Question: 63
Page: 278
Difficulty: 4 (Moderately Easy)
Category 1: Word Problems > Discount >
Category 2: Arithmetic > Percents > other

Explanation: Call store L's price x and M's price y. Each price is discounted, so each of those prices are reduced by some unknown amount.

Statement (1) is insufficient. M's discount is greater, but without knowing the original prices, we don't know which discount price is less. If both original prices are the same, M's discount price is less. If L's original price is substantially less than M's, L's discount price is less.

Statement (2) is also insufficient. Again, we don't know the original prices. If the original prices are the same, M's discount price is less, but if M's original price is much higher, L's discount price is less.

Taken together, the statements are sufficient. Given each store's discount in terms of both dollars and percentages, we can calculate the original prices. For instance, L's discount is 10 percent of the original price, which is $5. Thus, L's original price is $50 and its discount price is $45. By the same reasoning, M's original price is $40 and it's discount price is $34. Choice (C) is correct.

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