Form the pair of linear equations & find their solutions by elimination method :
Yash scored 40 marks in a test, getting 3 marks for each right answer and losing 1 mark for each wrong answer. Had 4 marks been awarded for each correct answer and 2 marks been deducted for each incorrect answer, then Yash would have scored 50 marks. How many questions were there in the test?
[Class 10 NCERT Ch:3]
Yash scored 40 marks in a test, getting 3 marks for each right answer and losing 1 mark for each wrong answer. Had 4 marks been awarded for each correct answer and 2 marks been deducted for each incorrect answer, then Yash would have scored 50 marks. How many questions were there in the test?
[Class 10 NCERT Ch:3]
Add an Answer
More Questions From This User See All
Answers & Comments
Verified answer
Hi govind,here is the required answer:-
Let the number of correct answers be 'x'
Then the number of incorrect answers be 'y'
According to the question,
3 marks for each right answer and losing 1 mark for each wrong answer.
Then the equation would be
3x - y = 40 -----------(1)
Had 4 marks been awarded for each correct answer and 2 marks been deducted for each incorrect answer,
For this the equation would be
4x-2y=50
2(2x-y)=2(25)
2x-y=25 ----------------(2)
Solving by elimination method,
(2)-(1)
2x-y = 25
3x-y= 40
_______
-x=-15
x=15
Substitute x value in (2),we get
2(15)-y=25
y=30-25
y=5
Therefore,the number of correct answers=15
Number of incorrect answers=5
Total no,of questions=15+5=20
★Hope it helps★
Verified answer
♠Answer♠That's a simple one .
Let 'x' Be the Correct Answers & 'y' be The Wrong Ones .
Than , By The First Statement ,
3x - y = 40
And , By Second Statement ,
4x - 2y = 50
So , Multiplying the First Statement by 2 ,
6x - 2y = 80
subtracting the second Equation from It ,
2x = 30
x = 15
& y = 5
Hence , Total Questions ,
x + y = 20 .
#SupermanINFINITY