Question 206235
Jonas takes a two-digit number and subtracts the sum of the digits from it. Which of the following answers is a possible result of the calculation? 
(A) 42 (B) 49 (C) 55 (D) 63 (E) Not enough information
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D.  This will always give a multiple of 9, and only D qualifies.
79 - 16 = 63
78 - 15 = 63
etc