Official Guide Explanation:
Data Sufficiency #50

Background

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Solution and Metadata

Question: 50
Page: 277
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Sets > 2 sets
Category 2: Word Problems > Sets >

Explanation: Judging from the question, this looks like a question that involves overlapping sets: there will be some directors of Companies K and R that overlap and others who don't. Statement (1) is not sufficient, but it does provide some information: 17 = (K directors) + (R directors) - (directors in both K and R). Statement (2) is also insufficient, as it gives no indication how much overlap there is.

Taken together, the statements are sufficient. According to (1): 17 = (K directors) + (R directors) - (directors in both K and R). (2) fills in some of those gaps:

17 = 12 + 8 - overlap

17 = 20 - overlap

overlap = 3

Thus, the correct choice is (C).

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