Riordan attempted all the 22 questions in a quiz and scored 16 marks. Given that 9 marks were awarded for each correct answer but 4 marks were deducted for each wrong answer. how many questions did Riordan answer correctly?
Number of
correct answers |
Marks
awarded |
Number of
wrong answers |
Marks
deducted |
Total
marks |
22
|
22 x 9
= 198 |
0 |
0 |
198 |
21
|
21 x 9
= 189 |
1 |
1 x 4
= 4 |
189 - 4
= 185 |
| 8 |
8 x 9
= 72 |
14 |
14 x 4
= 21 |
72 - 21
= 16 |
Total marks awarded if all the answers are correct
= 22 x 9
= 198
Big difference in marks deducted
= 198 - 16
= 182
Small difference in marks deducted
= 9 + 4
= 13
Number of wrong answers
= 182 ÷ 13
= 14
Number of correct answers
= 22 - 14
= 8
Answer(s): 8
