there are 180 multiple choice questions in a test a candidate gets f our marks for every correct answer and for every unattempted or wrongly answered questions 1 mark is deducted from the total score of correct answer if a candidate scored 450 marks in the test how many questions did he answer correctly
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let the correct answer be x
let the wrong answer be y
we make equation 1st and 2nd
x+y=180------------1st eq
4x-y=450---------2nd eq
by adding 1st and 2nd equation
x+y=180
4x-y=450
we get 5x=630
x= 630÷5
x=126
put the value of x in equation 1
x+y=180
126+y=180
y=180-126
y= 54
so the correct answers are 126 and wrong answers are 54
let the wrong answer be y
we make equation 1st and 2nd
x+y=180------------1st eq
4x-y=450---------2nd eq
by adding 1st and 2nd equation
x+y=180
4x-y=450
we get 5x=630
x= 630÷5
x=126
put the value of x in equation 1
x+y=180
126+y=180
y=180-126
y= 54
so the correct answers are 126 and wrong answers are 54
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