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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. 
      ?. x 4 ? 227 = 398
      ?. y 2 + 321 = 346

    • Options
    • A. 1
    • B. 2
    • C. 3
    • D. 4
    • Discuss
    • 2. If 6th March, 2005 is Monday, what was the day of the week on 6th March, 2004?

    • Options
    • A. Sunday
    • B. Saturday
    • C. Tuesday
    • D. Wednesday
    • Discuss
    • 3. 1, 4, 9, 16, 23, 25, 36

    • Options
    • A. 9
    • B. 23
    • C. 25
    • D. 36
    • Discuss
    • 4. 
      A sum of money is to be divided equally among P, Q and R in the respective ratio of 5 : 6 : 7 and another sum of money is to be divided between S and T equally. If S got ? 2100 less than P, then how much amount did Q receive?

    • Options
    • A. ? 2500
    • B. ? 2000
    • C. ? 1500
    • D. Couldn't be determined
    • Discuss
    • 5. 
      If a : b = b : c, then ratio a 4 : b 4 is equal to

    • Options
    • A. ac : b2
    • B. a2 : c2
    • C. c2 : a2
    • D. b2 : ac
    • Discuss
    • 6. 
      A man covers half of his journey at 6 km/h and the remaining half at 3 km/h. Find his average speed.

    • Options
    • A. 3 km/h
    • B. 4 km/h
    • C. 4.5 km/h
    • D. 9 km/h
    • Discuss
    • 7. 
      A person can walk a certain distance and drive back in 6 h. He can also walk both ways in 10 h. How much time will he take to drive both ways?

    • Options
    • A. 2 h
    • B. 21/2 h
    • C. 51/2 h
    • D. 4 h
    • Discuss
    • 8. 
      Find the least number by which 175760 be devided to make it a perfect cube.

    • Options
    • A. 10
    • B. 20
    • C. 100
    • D. 5
    • Discuss
    • 9. 
      The roots of the equation x2 + px + q = 0 are equal if :

    • Options
    • A. p2 = 2q
    • B. p2 = 4q
    • C. p2 = - 4q
    • D. p2 = - 2q
    • Discuss
    • 10. 
      Two cubes have volumes in the ratio 1: 27, The ratio of their surface areas is?

    • Options
    • A. 1 : 3
    • B. 1 : 8
    • C. 1 : 9
    • D. 1 : 18
    • Discuss


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