Question

In an examination there are 100 questions 4marks each correct answer and 2 marks for each wrong answer. If surya attempt all the questions and score 40 marks. Find the number of questions he answered wrongly

Answer 1

Answer:

72 wrong answers then only he can get 40

Answer 2

Answer:

$\sf\large\underline{Let:-}$

$\sf{\implies The\: number\:_{(correct\:question)}=x}$

$\sf{\implies The\: number\:_{(wrong\:question)}=x}$

$\sf\large\underline{To\:Find:-}$

$\sf{\implies The\: number\:_{(correct\:question)}=?}$

$\sf\large\underline{Solution:-}$

To calculate the number of correct question which is given by Herman at first we have to focus on the given Question after that we have to set up equation then solve the equation by solving we get the number of correct question.

$\sf{\implies Calculation\:for\:1st\:equation:-}$

$\sf{\implies Number\:_{(correct\:Q)}-1=Number\:_{(wrong\:Q)}}$

$\tt{\implies x-1=y}$

$\tt{\implies x-y=1---(i)}$

$\sf{\implies Calculation\:for\:2nd\:equation:-}$

$\sf{\implies mark\:_{(correct\:Q)}-mark\:_{(wrong\:Q)}=Total\:_{(marks)}}$

$\tt{\implies 4x-y=40-----(ii)}$

In eq (i) multiply by 4 then subract from (ii):-]

$\tt{\implies 4x-4y=4}$

$\tt{\implies 4x-y=40}$

By solving we get here:-]

$\tt{\implies -3y=-36}$

$\tt{\implies y=12}$

Putting the value of y=12 in eq (i):-]

$\tt{\implies x-y=1}$

$\tt{\implies x-12=1}$

$\tt{\implies x=1+12}$

$\tt{\implies x=13}$

$\sf\large{Hence,}$

$\sf{\implies The\: number\:_{(correct\:question)}=13}$