CEMC Pascal, 2011

Algebra Difficulty 1.0 Junior Find the answer Canada

Peyton puts 30 L of oil and 15 L of vinegar into a large empty can. He then adds 15 L of oil to create a new mixture. What percentage of the new mixture is oil?

(A) $75$ (B) $25$ (C) $45$ (D) $50$ (E) $60$

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