Question

John is having an exam with Questions that require many answers.The Exam has 20 questions.

For every Correct answer he Gets 5 points and for every mistake he Loses 2 points.
John answers all of questions and in the end he receives 51 points.
*HOW MANY CORRECT ANSWERS ARE THERE?*

Answer 1

to get 52 marks there has to be a combo of right and wrongs marks.

i just used trial and error, and logic that there must me more right than wrong to get::

13 right answers (13x5=65)

+ 7 wrong (-2x7=-14)

65-14=51