P is three times as old as Q. In 10 years, P will be twice as old as Q. How old was P three years ago?  Answers
A) 27  B) 30  C) 33  D) 36  E) 39
P = 3Q so Q = P/3   P+10 = 2(Q+10) = 2(P/3+10)   P/3 = 10   P = 30   Three years ago, P was 27.   The answer is 27.
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P is three times as old as Q. In 10 years, P will be twice as old as Q. How old was P three years ago?