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  1. For a natural no. b, let N(b) denote the no. Of natural numbers a for which the equation x²+ax+b =0 has integer roots.what is the smallest value of b for which N(b)=20?

    How to solve above question.
    Himanshu

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  2. let A and B together have n marbles Where n is greater than zero A says to be if I give you some Marbles then you will have twice as many Marbles as I will have then B says to A if I give you some Marbles then you will have thrice as many Marbles as I will have what is the minimum possible value of n from the above statements if they are true
    - himanshu

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    Replies
    1. For 1st. Condition
      x + 2x = m
      =}3x=m ie 3 is a factor of m
      For 2nd condition
      x + 3x = m
      =}4x = m ie 4 is also a factor of m

      Least no- lcm of 3 & 4 = 12
      1-(8,4)
      2-(3,9)

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    2. Assume, there are n no. of marbles. Initially, A having x marbles . So, B get
      n-x marbles.
      Now , A gives a1 marbles to B
      therefore, 2(x-a1)=(n-x+a1).........(1)
      Now, B gives a2 marbles to A
      therefore, x+a2= 3(n-x-a2)........(2)
      From 1 and 2 after eleminating x ,we get
      n=12(a1+a2)/5
      For n to be smallest natrural no.
      a1+a2=5
      therefore, n=12

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  3. there are n - 1 Redballs n green balls and n + 1 blue balls in a bag the number of ways of choosing 2 balls from the bag that have different colour is 299 what is the value of n
    _himanshu

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  4. (n+1)(n)+(n)(n-1)+(n-1)(n+1)=299
    therefore n=10

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  7. Answer is 1.
    See the solution p-rmo 2015 Q.17 which I have published on my blog.

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