Question

to discourage random guessing on a multiple- choice exam, the professor assigns 5 points for a correct response, deducts 3 points for an incorrect answer, and gives 0 points for leaving the question blank. what is the student's score on a 31 question exam if he has 21 correct answers and 10 incorrect?

Answer 1

Well, if he had 21 questions answered correct, and 10 incorrect, we know 21 + 10 = 31, so he did not leave any questions blank.

Now to solve this we must add the points given and taken between 21 questions correct, and 10 questions incorrect.

If he gets 5 points every correct answer, and he has 21 correct answers, we multiply 21 x 5, so what is 21 x 5?