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Home Aptitude Simplification See What Others Are Saying!
  • Question
  • Mohan gets 3 marks for each correct sum and loses 2 marks for each wrong sum. He attempts 30 sums and obtains 40 marks. The number of sums solved correctly is


  • Options
  • A. 25
  • B. 10
  • C. 15
  • D. 20

  • Correct Answer
  • 20 

    Explanation

    Solution 1.
    Let the question solved correctly by Mohan = X ;
    and number of question solved wrongly by Mohan = 30 - X ;
    According to the question,
    3X - (30 - X) x 2 = 40
    ? 3x - 60 + 2x = 40
    ? 5x - 60 = 40
    ? 5x = 40 + 60 ? x = 100/5 = 20
    ? Mohan attempted 20 questions correctly .

    Solution 2.
    Let the question solved correctly by Mohan = X ;
    and number of question solved wrongly by Mohan = Y ;
    According to given question;
    X + Y = 30 ; -----------i
    3X - 2Y = 40 ;-------ii

    Now multiply the first equation by 2;
    we will get
    2X + 2Y = 60 ;--------iii
    After Add the equation ii and iii , we will get
    3X - 2Y + 2X + 2Y = 40 + 60 ;
    ? 5X = 100 ;
    ? X = 20;

    ? Mohan attempted 20 questions correctly .


  • More questions

    • 1. 
      The median for the data 2, 4, 6, 8, 10, 12, 14 is

    • Options
    • A. 6
    • B. 8
    • C. 9.5
    • D. 10
    • Discuss
    • 2. 
      The value of 47 / 10000 is?

    • Options
    • A. .0047
    • B. .0470
    • C. .00047
    • D. .000047
    • Discuss
    • 3. If 4x = 18y, then the value of ( x/y - 1) is

    • Options
    • A. 1 3
    • B. 7 2
    • C. 2 3
    • D. 3 2
    • Discuss
    • 4. 
      If the price of 23 toys is Rs. 276, then what will the price (Rs.) of 12 toys?

    • Options
    • A. 144
    • B. 158
    • C. 159
    • D. 166
    • Discuss
    • 5. 
      .02 =(......?.....)%

    • Options
    • A. 20
    • B. 2
    • C. .02
    • D. .2
    • Discuss
    • 6. 
      If 36 men can do a piece of work in 25 hours, in how many hours will 15 men do it?

    • Options
    • A. 45
    • B. 55
    • C. 60
    • D. 72
    • Discuss
    • 7. 
      2?63 / 11 =233

    • Options
    • A. 4
    • B. 3
    • C. 6
    • D. 5
    • Discuss
    • 8. 
      When 121012 is divided by 12, the remainder is

    • Options
    • A. 0
    • B. 2
    • C. 3
    • D. 4
    • Discuss
    • 9. 
      Aarti can do a piece of work in 6 days. In how many days will she complete three time of work of same type?

    • Options
    • A. 18 days
    • B. 21 days
    • C. 3 days
    • D. 6 days
    • Discuss
    • 10. 
      750.0003 ÷ 19.999 =?

    • Options
    • A. 49
    • B. 18
    • C. 22
    • D. 38
    • Discuss


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