Adam scores a total of 39 marks.
There are a total of 30 questions.
Every correct answer will earn 3 marks.
Every wrong answer will earn 0 marks.
How many questions are (a) incorrectly answered and (b) correctly answered?
Number of correct answers |
Marks earned |
Number of incorrect answers |
Total marks |
30 |
30 x 3 = 90 |
0 |
90 |
29 |
29 x 3 = 87 |
1 |
87 |
13 |
13 x 3 = 39 |
17 |
39 |
(a)
Total score if Adam answers all the questions correctly
= 30 x 3
= 90
Total score if Adam answers one question wrongly
= 29 x 3
= 87
Big difference in marks deducted
= 90 - 39
= 51
Small difference in marks deducted
= 90 - 87
= 3
Number of questions answered incorrectly
= 51 ÷ 3
= 17
(b)
Number of questions answered correctly
= 30 - 17
= 13
Answer(s): (a) 17; (b) 13