Ahmad attempted all the 30 questions in a quiz and scored 18 marks. Given that 6 marks were awarded for each correct answer but 3 marks were deducted for each wrong answer. how many questions did Ahmad answer correctly?
Number of
correct answers |
Marks
awarded |
Number of
wrong answers |
Marks
deducted |
Total
marks |
30
|
30 x 6
= 180 |
0 |
0 |
180 |
29
|
29 x 6
= 174 |
1 |
1 x 3
= 3 |
174 - 3
= 171 |
| 12 |
12 x 6
= 72 |
18 |
18 x 3
= 29 |
72 - 29
= 18 |
Total marks awarded if all the answers are correct
= 30 x 6
= 180
Big difference in marks deducted
= 180 - 18
= 162
Small difference in marks deducted
= 6 + 3
= 9
Number of wrong answers
= 162 ÷ 9
= 18
Number of correct answers
= 30 - 18
= 12
Answer(s): 12
