Adam scores a total of 30 marks.
There are a total of 70 questions.
Every correct answer will earn 2 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 |
70 |
70 x 2 = 140 |
0 |
140 |
69 |
69 x 2 = 138 |
1 |
138 |
15 |
15 x 2 = 30 |
55 |
30 |
(a)
Total score if Adam answers all the questions correctly
= 70 x 2
= 140
Total score if Adam answers one question wrongly
= 69 x 2
= 138
Big difference in marks deducted
= 140 - 30
= 110
Small difference in marks deducted
= 140 - 138
= 2
Number of questions answered incorrectly
= 110 ÷ 2
= 55
(b)
Number of questions answered correctly
= 70 - 55
= 15
Answer(s): (a) 55; (b) 15