Adam scores a total of 30 marks.
There are a total of 90 questions.
Every correct answer will earn 5 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 |
90 |
90 x 5 = 450 |
0 |
450 |
89 |
89 x 5 = 445 |
1 |
445 |
6 |
6 x 5 = 30 |
84 |
30 |
(a)
Total score if Adam answers all the questions correctly
= 90 x 5
= 450
Total score if Adam answers one question wrongly
= 89 x 5
= 445
Big difference in marks deducted
= 450 - 30
= 420
Small difference in marks deducted
= 450 - 445
= 5
Number of questions answered incorrectly
= 420 ÷ 5
= 84
(b)
Number of questions answered correctly
= 90 - 84
= 6
Answer(s): (a) 84; (b) 6