Question

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?  Number of questions he has attempted correctly =  10 Number of questions he has attempted incorrectly =  10 Number of questions he has attempted incorrectly =  6 Number of questions he has attempted incorrectly =  11

Solution

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

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