In a class test (+3) marks are given for every correct answer and (−2) marks are given for every incorrect answer and no marks for not attempting a question. Rakesh scores 18 marks by attempting 16 questions. How many questions has he attempted correctly and how many has he attempted incorrectly?
In a class test (+3) marks are given for every correct answer and (−2) marks are given for every incorrect answer and no marks for not attempting a question. Rakesh scores 18 marks by attempting 16 questions. How many questions has he attempted correctly and how many has he attempted incorrectly?
The correct options are
A Number of questions he has attempted correctly = 10
C Number of questions he has attempted incorrectly = 6
Marks obtained for 1 right answer = +3
Marks obtained for 1 wrong answer = −2
Total marks scored by Rakesh = 18
Number of questions attempted = 16
Let number of correct answers be x.
∴ Number of incorrect answers = (16 - x )
⇒ 3x + (16 - x)(-2) = 18
⇒ 3x - 32 + 2x = 18
⇒ 5x = 18 + 32
⇒ 5x = 50
⇒ x = 10
Therefore number of questions answered correctly = 10
Number of questions answered incorrectly = 16 - 10 = 6
A
Number of questions he has attempted correctly = 10
C
Number of questions he has attempted incorrectly = 6
Marks obtained for 1 right answer = +3
Marks obtained for 1 wrong answer = −2
Total marks scored by Rakesh = 18
Number of questions attempted = 16
Let number of correct answers be x.
∴ Number of incorrect answers = (16 - x )
⇒ 3x + (16 - x)(-2) = 18
⇒ 3x - 32 + 2x = 18
⇒ 5x = 18 + 32
⇒ 5x = 50
⇒ x = 10
Therefore number of questions answered correctly = 10
Number of questions answered incorrectly = 16 - 10 = 6
