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 9 questions, if Sterling had answered 2 more questions correctly, he would have earned 31 pieces of candy. How many of the 9 questions did Zachary answer correctly?	Choices
A) 6	B) 7	C) 8	D) 9	E) 10

Rationale: "i got two equations : 3 x - 2 y = 25 x + y = 9 3 x - 2 ( 9 - x ) = 25 3 x - 18 + 2 x = 25 5 x = 43 x = 8.6 or between 8 and 9 . ( ans c )"
Answer: C