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CEMC Gauss (Grade 8), 2009

Combinatorics Difficulty 2.0 Junior Find the answer Canada

In a class of 40 students, 18 said they liked apple pie, 15 said they liked chocolate cake and 12 said they did not like either. How many students in the class liked both?

(A) $15$ (B) $10$ (C) $3$ (D) $7$ (E) $5$

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