Ken attempted all the 15 questions in a quiz and scored 15 marks. Given that 7 marks were awarded for each correct answer but 3 marks were deducted for each wrong answer. how many questions did Ken answer correctly?
Number of
correct answers |
Marks
awarded |
Number of
wrong answers |
Marks
deducted |
Total
marks |
15
|
15 x 7
= 105 |
0 |
0 |
105 |
14
|
14 x 7
= 98 |
1 |
1 x 3
= 3 |
98 - 3
= 95 |
| 6 |
6 x 7
= 42 |
9 |
9 x 3
= 14 |
42 - 14
= 15 |
Total marks awarded if all the answers are correct
= 15 x 7
= 105
Big difference in marks deducted
= 105 - 15
= 90
Small difference in marks deducted
= 7 + 3
= 10
Number of wrong answers
= 90 ÷ 10
= 9
Number of correct answers
= 15 - 9
= 6
Answer(s): 6
