In a quiz program the correct answer gets you 2 marks. For each wrong answer, one mark is deducted from the total score. There are 50 questions to be answered. If Preeti scored 76 marks , how many of her questions were right?
A
26
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B
13
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C
42
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D
38
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Solution
The correct option is C
42
As the number of questions answered is unknown, let us assume that unknown variable as 'x'. If the number of questions answered correctly are x, then the number of questions answered incorrectly will be (50−x). For each correct answer, she gets 2 marks. So the marks scored for x correctly answered questions are 2x. Similarly, the marks scored for (50-x) incorrectly answered questions are (50−x)×1=50−x Now, the total marks scored by Preeti will be 2x- (50 -x) = 2x -50 +x = 3x -50 (For each wrong answer, one mark is deducted from the total score)
The final equation is, 3x -50 = 76 3x = 50 +76 = 126 x=1263=42 So, the total number of questions answered correctly by Preeti are 42.