Official Guide Explanation:
Data Sufficiency #27




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Solution and Metadata

Question: 27
Page: 155
Difficulty: 4 (Moderately Easy)
Category 1: Word Problems > Other >
Category 2: Algebra > Linear Equations-One Unk >

Explanation: Statement (1) is sufficient: it has one linear equation with one variable. Ricky (r) is twice as old now as he was 8 years ago (2(r - 8)), so:

r = 2(r - 8)

r = 2r - 16

16 = r

Statement (2) is insufficient: it has only one linear equation, but introduces a second variable, Teresa's age. Choice (A) is correct.

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