Question

There are 180 multiple choixe questions in a test a candidate gets 4 marks for every correct answer and for every un attempted or wrong answered question one mark is deducted from the total score of correct answers if a candidate scored 450 marks in thetest hw many questions did he answered correctly

Answer 1

$4x - x = 450 \\ 3x = 450 \\ x = 450 \div 3 \\ x = 150$