jade63762
contestada

PLEASE HELP WITH THIS MATH SUM

David answered 60 questions in a test. For every correct answer, he received 4 marks. For
every incorrect answer, 7 marks were deducted from his final score. He scored 108 marks.
How many questions did David answer correctly?

Respuesta :

Darth21

Answer:

27 questions correct

Step-by-step explanation:

Well 108 marks and 4 marks for each correct,techinally you can’t subtract since 108 is the final score, and the thing was already subtracted so \divide.

108/4= 27

27 correct answers

debmc7

How many questions did David answer correctly? David answered 48 questions correctly.

We’ll call the number of correct answers a, incorrect answers b.
60 questions on the test gives us:
a + b = 60
And the scoring gives us:
4a - 7b = 108

First we’ll solve for a in terms of b:
a = 60 - b
The we’ll substitute that value for a in the second equation to get a numerical value for b:

4(60 - b) - 7b = 108
240 - 4b - 7b = 108
-11b = -132
b = 12

Now we go back to the first equation and get a numerical value for a:
a = 60 -b
a = 60 - 12
a = 48

Check the math with the scoring equation:
4(48) - 7(12) =
192 - 84 = 108

Please lmk if you have any questions.

Otras preguntas