Official Guide Explanation:
Data Sufficiency #60

Background

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Solution and Metadata

Question: 60
Page: 157
Difficulty: 5 (Moderate)
Category 1: Algebra > Linear Equations-Two Unk >
Category 2: Geometry > Quadrilaterals >
Category 3: Word Problems > Geometry Problems >

Explanation: Perimeter is given by 2l + 2w, so for this garden, 2l + 2w = 360. To solve for the length, we need another linear equation. Statement (1) is sufficient: l = 2w can be combined with the perimeter equation to solve for each variable. Statement (2) is insufficient: if the length is greater than the width, l - w = 60; if not, w - l = 60. Since we don't know which equation is true, we can't find the length of the garden. Choice (A) is correct.

[Note: The answer given in the book is (D). The explanation in the book suggests that the length must be longer than the width, which is not true. It's also not consistent with other published GMAT questions. Until and unless the wording of the question is changed in future editions, (A) is the correct answer.]

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