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  • Question
  • On March 1st 2016 , sherry saved ? 1. Everyday starting from March 2nd 2016, he save ?1 more than the previous day . Find the first date after March 1st 2016 at the end of which his total savings will be a perfect square.


  • Options
  • A. 17th March 2016
  • B. 18th March 2016
  • C. 26th March 2016
  • D. None of these

  • Correct Answer
  • None of these 

    Explanation

    According to the question,
    Every day adding 1 rs extra to previous day.
    Let us assume after n day, total saving will become perfect square.
    1 + 2 + 3 + 4 + 5 + 6 +.......................+ tn.
    Apply the algebra A.P formula,
    sum of total rupees after n days = n(n+1)/2
    Hit and trail method, Put the value of n = 2 , 3 , 4, 5 .... and so on to get the perfect square.
    If n = 2
    n(n+1)/2 = 2 x 3 / 2 = 3 which is not perfect Square.
    If n = 3
    n(n+1)/2 = 3 x 4 / 2 = 6 which is not perfect Square.
    If n = 4
    n(n+1)/2 = 4 x 5 / 2 = 10 which is not perfect Square.
    If n = 5
    n(n+1)/2 = 5 x 6 / 2 = 15 which is not perfect Square.
    If n = 6
    n(n+1)/2 = 6 x 7 / 2 = 21 which is not perfect Square.
    If n = 7
    n(n+1)/2 = 7 x 8 / 2 = 28 which is not perfect Square.
    If n = 8
    n(n+1)/2 = 8 x 9 / 2 = 36 which is perfect Square.

    n(n+1)/2 should be a perfect square . The first value of n when this occurs would be for n = 8. thus , on the 8th of March of the required condition would come true.


  • More questions

    • 1. 
      A and B together can complete a work in 3 days. They started together but after 2 days, B left the work. If the work is completed after 2 more days, B alone could do the work in how many days?

    • Options
    • A. 5
    • B. 6
    • C. 7
    • D. 10
    • Discuss
    • 2. 
      A wheel makes 1000 revolutions in covering a distance of 88 km. the diameter of the wheel is?

    • Options
    • A. 24 meters
    • B. 40 meters
    • C. 28 meters
    • D. 14 meters
    • Discuss
    • 3. 25, 36, 49, 81, 121, 169, 225

    • Options
    • A. 36
    • B. 49
    • C. 121
    • D. 169
    • Discuss
    • 4. 
      (.896 x .752 +.896 x .248) / (.7 x .034 + .7 x.966) =?

    • Options
    • A. 1.28
    • B. 0.976
    • C. 12.8
    • D. 9.76
    • Discuss
    • 5. 
      Einstein goes from Ahmedabad To Lucknow at the speed of 40 km/hr and returned at the speed of 60 km/hr .the average speed of Einstein during the whole journey is

    • Options
    • A. 48 km/hr
    • B. 24 km/hr
    • C. 50 km/hr
    • D. none of these
    • Discuss
    • 6. 
      Today is Monday. After 61 days, it will be

    • Options
    • A. Wednesday
    • B. Saturday
    • C. Tuesday
    • D. Thursday
    • Discuss
    • 7. 9548 + 7314 = 8362 + (?)

    • Options
    • A. 8230
    • B. 8410
    • C. 8500
    • D. 8600
    • E. None of these
    • Discuss
    • 8. 
      The true discount on a certain sum due 1 yr hence at 30% per annum, is ? 240. What is the banker' discount on the same sum for the same time and at the same rate?

    • Options
    • A. ? 400
    • B. ? 212
    • C. ? 312
    • D. ? 445
    • Discuss
    • 9. 
      Calendar of month July is same as that of which month of previous year.

    • Options
    • A. May
    • B. September
    • C. April
    • D. None of these
    • Discuss
    • 10. 
      A coin is successively tossed two times. Find the probability of getting? (1) exactly one head (2)at least one head

    • Options
    • A. 1/2 , 3/4
    • B. 2/3, 1/4
    • C. 1/4, 4/5
    • D. 1/2, 2/3
    • Discuss


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