Official Guide Explanation:
Data Sufficiency #26




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Solution and Metadata

Question: 26
Page: 155
Difficulty: 4 (Moderately Easy)
Category 1: Word Problems > Other >
Category 2: Algebra > Linear Equations-One Unk >

Explanation: Statement (1) is sufficient, as it provides two equations with a total of two variables. The number of papers sold yesterday is 100, so y = 100. If that's 10 fewer than twice the number sold today, 2t - 10 = y. Substituting in the value of y, you can solve for the value of t, the number of papers sold today.

Statement (2) is insufficient: it also has two variables, but only offers one equation. Choice (A) is correct.

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