There are 90 multiple choice questions in a test. Suppose you get two marks for every correct answer and for every question you leave unattempted or answer wrongly, one mark is deducted from your total score of correct answers. If you get 60 marks in the test, then how many questions did you answer correctly?
SOLUTION: it is given that there are a total of 90 MCQs and we get 2 marks for a right answer and the negetive marking is -1, after the test, our total marks obtained is60.
this can be represented as:
90 - y = 60
ie, y = 90 - 60 = 30
therefore, we have lost a total of 30 marks !!!!
and the problem says that we get 2 marks for a right attempt,
so,60 / 2 =30 answers were correct . the rest were incorrect.
total nos of questions = 90
let no of questions answered correctly be x
no of questions answered incorrectly =90-x
total marks obtained = 60
marked obtained for correct answers =2x
marks deducted for wrong answers = -1(90-x) = -90 + x
therfore 2x - 90 + x = 60
2x + x = 60 + 90
3x = 150
x = 150/3
x = 50
Ans =so the no of questions answered correctly are 50