3 years ago, Paula was 3 times as old as Karl. In 9 years, Paula will be twice as old as Karl. What is the sum of their ages now? Select the correct option:  A) 42  B) 46  C) 50  D) 54  E) 58

Rationale: "p - 3 = 3 ( k - 3 ) and so p = 3 k - 6 p + 9 = 2 ( k + 9 ) ( 3 k - 6 ) + 9 = 2 k + 18 k = 15 p = 39 p + k = 54 the answer is d ."
Answer: D