Adam scores a total of 85 marks.
There are a total of 31 questions.
Every correct answer will earn 5 marks.
Every blank or wrong answer will have 2 marks deducted.
How many questions are (a) incorrectly answered and (b) correctly answered?
Number of correct answers |
Marks earned
|
Number of incorrect answers |
Marks deducted
|
Total score
|
31 |
31 x 5 = 155 |
0 |
0 |
155 - 0 = 155 |
30 |
30 x 5 = 150 |
1 |
1 x 2 = 2 |
150 - 2 = 148 |
21 |
105 |
10 |
10 x 2 = 20 |
105 - 20 = 85 |
(a)
Total score if Adam answers all the questions correctly
= 31 x 5
= 155
Total score if Adam answers one question wrongly
= 150 - 2
= 148
Big difference in total score
= 155 - 85
= 70
Small difference in total score
= 5 + 2
= 7
Number of questions answered incorrectly
= 70 ÷ 7
= 10
(b)
Number of questions answered correctly
= 31 - 10
= 21
Answer(s): (a) 10; (b) 21