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

Number of total questions = 180

Let the candidate answers questions correctly = x

$\therefore$ Uncorrect or unattend questions = 180 - x total score he got = 450

According to the condition

$x\times 4-(180-x)\times 1=450$

$\Rightarrow 4x-180+x=450$

$\Rightarrow 5x=450+180=630$

$\Rightarrow x=\frac{630}{5}=126$

Number of question which answered correctly = 126