On a standardized multiple choice test, 3 points were awarded for a correct answer, while a wrong answer caused a deduction of 1 point, and no points were awarded or deducted for omitted questions If Marjorie received a score of 84 when she omitted 4 of the 40 questions on the test, how many did she get right? How many did she get wrong?

She got 30 questions right and 6 questions wrong.

Step-by-step explanation:

Let x = Number of correct questions, y = Number of wrong questions

As Award for each correct answer = +3 points and Award for each wrong answer = -1 point.

Total score = 3x-1y

If Marjorie omitted 4 of the 40 questions, then she did 40-4=36 questions.

Now, x+y = 36 (1)

and 3x-y =84   (2)  (as she scored 84)

Adding (1) and (2), we get

4x = 120

Divide both sides by 4, we get

x= 30

y = 36-30=6

hence, she got 30 questions right and 6 questions wrong.