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?

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.

Zero is the mid point of the line segment