Zachary is helping his younger brother, Sterling, learn his multiplication tables. For every question that Sterling answers correctly, Zachary gives him 3 pieces of candy. For every question that Sterling answers incorrectly, Zachary takes away two pieces of candy. After 14 questions, if Sterling had answered 2 more questions correctly, he would have earned 31 pieces of candy. How many of the 14 questions did Zachary answer correctly?  Pick.
A) 6 B) 7 C) 8 D) 9 E) 10

Rationale: i got two equations : 3 x - 2 y = 25 x + y = 14 3 x - 2 ( 14 - x ) = 25 3 x - 28 + 2 x = 25 5 x = 53 x = 10.6 or between 10 and 11 . ( ans e )
Answer: E