In an examination, a student attempted 23 questions and
secured 45 marks. If for every correct answer, 3 marks were
awarded and for every wrong answer, 1 mark was deducted,
then how many of his answers were wrong?
Options:
(A) 4
(B) 6
(C) 3
(D) 9
Answers
Answer:
B 6
Step-by-step explanation:
Suppose, number of correct answers is x and number of incorrect answers is y then,
x + y = 23
Now, for correct answer 3 marks are awarded therefore the student gets 3x marks for correct answer and for incorrect answer 1 mark is deducted so the student loses y marks for wrong answers therefore total marks will be the sum of marks obtained by correct and incorrect answers,
3x + (- y) = 45 (y is negative as we lose marks)
substitute x from the first equation, we get x = 23 - y
we replace x in second equation,
3(23-y) + (- y) = 45
69 - 3y +(- y) = 45
69 - 4y = 45
69 - 45 = 4y
4y = 24
y=6
As y was assumed the number of incorrect answers,
the student answered 6 questions incorrectly.
Answer:
answer is 6 it help u
Step-by-step explanation:
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