There are 80 questions in a test. Each correct answer
fetches 1 mark, each wrong answer & unanswered
question attract a penalty of 1/4 mark & 1/8 mark
respectively each. Frodo scored 23 marks in the test.
What is the minimum possible number of the ques-
tion wrongly answered by him?
Answers
Answer:
I think you want to ask how are such questions solved
If x answers were correct and y were wrong
then x-o.5y= 54.5 --- (1)
and
assuming he/she attempted all questions
x+y = 80 ----(2)
solving 1 and 2
1.5y = 25.5 => y = 17
If the number of questions attempted are variable, then you have to put a constraint that x+y can only be an integer
The second constraint is 1.5y should have .5 as the least significant figure (after decimal)
The third constraint is y can never be more than 17
suppose y is 16, then 1.5 y is 24, which breaks the second constraint
suppose y is 15, then 1.5 y is 22.5, which is a valid answer if he/she attempted 77 questions, x is 62 in this case.
(Another way to achieve the same is decreasing the number of x by 1 and y by 2 to get the same result, only varying the number of attempts)
solving this way following are set of answers
------------------------------------------
attempted questions x y
------------------------------------------
80 63 17
77 62 15
74 61 13
71 60 11
68 59 9
65 58 7
62 57 5
59 56 3
56 55 1
Step-by-step explanation:
Answer:
HEY MATE HERE IS YOU ANSWER
Step-by-step explanation:
Here is losing total of 67 marks in test (from the all correct situation)
If he answers a question wrongly, he should drop by 1.25 marks
If he leaves a question unanswered, he is losing 1.125 marks
Going through options, we find that
For option 1)
⇒ Marks lost by questions = 2.5
⇒ Marks required to be lost by unanswered ques. = 64.5
But 64.5 / 1.125 is not an integer.
Hence, it is not possible
For option 2)
⇒ Marks lost by question = 6.25
⇒ Marks required to be lost by unanswered ques. = 60.75
Here, 60.75 / 1.125 is an integer.
Hence, it is possible
Other two options also doesn’t give an integer.
∴ The minimum number of wrong answers is 5.
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