Question

There are 180 multiple choice questions in a test. If a candidate gets 4 marks for every correct answer and for every unattempted or wrongly answered question one mark is deducted from the total score of correct answers. If a candidate scored 450 marks in the test, how many questions did he answer correctly?

Answer 1

Let the number of correctly answered questions be x .
Therefore, the number of unattempted or wrongly answered questions will be (180 - x) . 
According to the question, 
4x - 1(180 - x) = 450
or 5x = 450 + 180
or \[x = \frac{630}{5} = 126\]
Thus, number of correctly answered questions = 126 . 
Number of unattempted or wrongly answered questions = 180 - 126 = 54 .