Answer:
20 questions
Step-by-step explanation:
Given
[tex]Correct \Marks= +5[/tex]
[tex]Incorrect\ Marks= -2[/tex]
[tex]Score\ Obtained = 30[/tex]
[tex]Number\ of\ correct\ answers = 10[/tex]
Required
Number of questions answered
First, we need to get the total correct marks obtained by Roy
This is calculated by multiplying the correct marks by number of correct answers
[tex]Total = +5 * 10[/tex]
[tex]Total = +50\ marks[/tex]
Subtract this from the total scores obtained; This gives the total incorrect answer obtained by Roy
[tex]Incorrect = Scores\ Obtained - Total[/tex]
[tex]Incorrect = 30 - (+50)[/tex]
Open bracket
[tex]Incorrect = 30 - 50[/tex]
[tex]Incorrect = -20[/tex]
Divide this by -2 to get the number of incorrect answers
[tex]Incorrect\ Answers = \frac{-20}{-2}[/tex]
[tex]Incorrect\ Answers = 10[/tex]
Add this to the number of correct answers to give the total number of question answered
[tex]Total = Correct\ Answers + Incorrect\ Answers[/tex]
[tex]Total = 10 + 10[/tex]
[tex]Total = 20[/tex]
Hence, Roy answered a total of 20 questions
