There are 180 multiple choice questions in a test. A candidate gets 4 marks for every correct answer, and for every un-attempted or wrongly answered questions 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?
Answers
Answered by
66
let no of correct ans = x
and no .of incorrect ans or unattemped ans = y
equation for total number of questions
x + y = 180 .....(1)
equation for marks scored
4x - y = 450 ......(2)
equate 1 and 2 we get
5x = 630
x = 126
y = 54
for checking substitute value in eq. 2
(4×126)-54= 450
and no .of incorrect ans or unattemped ans = y
equation for total number of questions
x + y = 180 .....(1)
equation for marks scored
4x - y = 450 ......(2)
equate 1 and 2 we get
5x = 630
x = 126
y = 54
for checking substitute value in eq. 2
(4×126)-54= 450
Answered by
18
Answer:
Correct answer 126
Step-by-step explanation:
let be no.of correct answer=x
for wrong answer. =180-x
total score d Mark s. =450
Total questions. =180
no.of marks correct= 4x
no.of. wrong answer=(180-x)*1
4x-(180-x)1=450
4x-180+X. =450
5x-180. = 450
5x. =450+180
5x. =630
x. =630/5
x=126 is the correct answer
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