Adam scores a total of 40 marks.
There are a total of 100 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 |
100 |
100 x 2 = 200 |
0 |
200 |
99 |
99 x 2 = 198 |
1 |
198 |
20 |
20 x 2 = 40 |
80 |
40 |
(a)
Total score if Adam answers all the questions correctly
= 100 x 2
= 200
Total score if Adam answers one question wrongly
= 99 x 2
= 198
Big difference in marks deducted
= 200 - 40
= 160
Small difference in marks deducted
= 200 - 198
= 2
Number of questions answered incorrectly
= 160 ÷ 2
= 80
(b)
Number of questions answered correctly
= 100 - 80
= 20
Answer(s): (a) 80; (b) 20