Question 1
**General instructions.** Answer the following 10 questions, and show your detailed solution in the space provided after each question. Each question is worth 4 points. Time limit: 60 minutes.
John challenged Tom on to a general knowledge contest. For every answer Tom got right, John gave him 7 dollars and for every answer Tom got wrong, he had to give John 3 dollars. John asked 50 questions and at the end of the competition, when everything was added up, neither owned the other any money! How many questions did Tom answer correctly?
John challenged Tom on to a general knowledge contest. For every answer Tom got right, John gave him 7 dollars and for every answer Tom got wrong, he had to give John 3 dollars. John asked 50 questions and at the end of the competition, when everything was added up, neither owned the other any money! How many questions did Tom answer correctly?