6. In a Mathematics test, there are 60 questions. There is 2 marks for every correct answer, and marki
deducted for each unattempted question or wrong solution. If Zaheer got 50 marks, how many question
did he answer correctly?
Answers
Answer:
Number of correct answers = 30
Number of wrong or unattempted question = 30
Step-by-step explanation:
Let the no. of correct answer = x
∴ incorrect/unattempted question = 60-x (as total no. of question is 60)
∵ there is 2 marks for every correct answer total marks of correct answer = 2x
Similarly, deduction of marks in case of wrong or unattempted ).= (60 - x)*1/3 (as 1/3 is deducted for incorrect/unattempted answer which you forgot to mention!)
Considering the total marks obtained by the student is 50, the total marks Zaheer got = 2x - (60 - x)*1/3 = 50
=2x - 20 + x/3 = 50
=2x + x/3 = 50 + 20
=6x/3 + x/3 = 70
=7x/3 = 70
=7x = 210 (gets cross multiplied)
=x = 30
∵ x = 30, total no. of correct answer is also 30.
∴ incorrect or unattempted ones are also 30.
Cross check!
30*2+(30*(-1/3))
=60+(-10)
=50!
Conclusion!
∴ number of question Zaheer did correct = 30.
Hope you understood:)