Question

in a competitive examination there where 60 questions the correct answer would carry two marks and for incorrect answer one marks would be subtracted Yashwant had attempt all the questions and he got total 90 marks then how many questions he got wrong​

Answer 1

Answer:

Let No of Correct answers be x

Let No. of wrong answers be y

Let No. of Unattempted question be z

Given that He had attempted all the questions that means z = 0

Now, Total number of questions (x+y+z)=60

⇒x+y=60 _________ (i)

No. of marks awarded for each correct answers = 2

Total Number of marks for correct answers = (No. of correct answers)*(Marks awarded for each correct answer)

Total Number of marks for correct answers = x*2=2x

Similarly No. of marks awarded for each wrong answers = -1

Similarly No. of marks awarded for each wrong answers = (No. of wrong answers)*(Marks awarded for each wrong answer)

Total Number of marks for wrong answers = y*(-1)=-y

Total marks 90 =  

(No. of marks awarded for each correct answers) + (Total Number of marks for wrong answers)

⇒ 90 = 2x-y _________ (ii)

From (i) we get y = 60-x

Substituting Value of y above in (ii)

⇒90 = 2x-(60-x)

⇒90 = 2x-60+x

⇒90 = 3x-60

⇒3x=150

⇒x=50

Now,  

⇒y = 60 - x

⇒y=60-50

⇒y=10

Therefore, x=50 & y=10

Answer 2

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killer

ace killer

the answer for your question

detailed answer

yashwant attempted all questions in the exam

so from that questions some may be right and some may be wrong

so let the correct answers be X and incorrect be y

so total questions were 60 so

$x + y = 60 \: \: \: \: \: (i)$

now the marking scheme for correct answer was 2 marks

and if the answer is incorrect then 1 mark will be deducted so it will be -1

so

in this exam he go 90 marks

so the equation will be

$2x - 1y = 90$

therefore we get

$2x - y = 90 \: \: \: \: \: \: \: (ii)$

so in eq i we have

$x + y = 60$

so

$y = 60 - x$

substitute the value of y in eq ii
so we get
2x-(60+x)=90
therefore
2x-60+x=90
3x=90+60
3x=150
X=150/3
x= 50
substitute value of x in eq i
50+y=60
y=60-50
y=10

hence the no. of correct answer yashwant attempted were 50 and incorrect answers were 10