chetan2u
In a medical enterance examination conducted at national level, each correct answer gets the candidate four marks, while each incorrect answer results in a negative marking of one mark. There were no negative marking for an unanswered question.
It is known that Aditya answered at least one question incorrectly, and there were a total of 30 questions.
Select for
Maximum score the maximum possible score that Aditya could have got, and select for
Impossible score the score that Aditya cannot score. Make only two selections, one in each column.
The maximum score a person can get is 4*30 or 120, when all questions are correct. However, we know that the student scores at least one question wrong.
Maximum score: Apart from the question wrong, the student answers all other questions correctly and scores 4*29 - 1 = 115.
Impossible score: If the highest score that the student can get is 115, surely he can never get 116.
The catch is that each incorrect answer results in -5 and each unanswered question results in -4 from the maximum score of 120.
All other scores are possible as we can always increase or decrease the number of unanswered questions.