2. Questions Bank
  3. 8th Class
  4. Mathematics
  5. Linear Equations in One Variable

8th Class Mathematics Linear Equations in One Variable Question Bank Linear Equations in one Variable

  • question_answer
    In an examination, a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer. If he attempts in all 40 questions and scored 120 marks, the number of questions he attempts incorrectly is: -

    A)  8   

    B)  32             

    C)  16                               

    D)  12

    Correct Answer: A

    Solution :

    (a): Let correctly attempted Q's be n Incorrectly attempted \[Q's=40-n\] \[\Rightarrow n\times 4+(40-n)(-1)=120\] \[\Rightarrow 4n-\left( 40-n \right)=120\] \[\Rightarrow 5n-40=120\] \[\Rightarrow 5n=160\] \[n=32\] \[\Rightarrow 40-n=8.\]   


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