Carl attempted all the 17 questions in a quiz and scored 10 marks. Given that 9 marks were awarded for each correct answer but 2 marks were deducted for each wrong answer. how many questions did Carl answer correctly?
Number of
correct answers |
Marks
awarded |
Number of
wrong answers |
Marks
deducted |
Total
marks |
17
|
17 x 9
= 153 |
0 |
0 |
153 |
16
|
16 x 9
= 144 |
1 |
1 x 2
= 2 |
144 - 2
= 142 |
| 4 |
4 x 9
= 36 |
13 |
13 x 2
= 16 |
36 - 16
= 10 |
Total marks awarded if all the answers are correct
= 17 x 9
= 153
Big difference in marks deducted
= 153 - 10
= 143
Small difference in marks deducted
= 9 + 2
= 11
Number of wrong answers
= 143 ÷ 11
= 13
Number of correct answers
= 17 - 13
= 4
Answer(s): 4
