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If between 1 and 1/31 there are n H.M's ...

If between 1 and 1/31 there are n H.M's and ratio of 7th and `(n-1)^th` harmonic means is 9:5, then values of n is

A

12

B

13

C

5

D

14

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The correct Answer is:
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PATHFINDER-PROGRESSION AND SERIES -QUESTION BANK
  1. If H1,H2,H3,.......Hn be n harmonic means between a and b then (H1+a)...

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  2. If a,b,c are in AP and a^2,b^2,c^2 are in HP, then

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  3. If between 1 and 1/31 there are n H.M's and ratio of 7th and (n-1)^th ...

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  4. (a^(n+1)+b^(n+1))/(a^n+b^n) is AM/GM/HM, between a and b if n is equal...

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  5. Sum of infinite terms of series 3+5. 1/4+7. 1/4^2+..... is

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  6. The value of x for which 1/(1+sqrtx),1/(1-x),1/(1-sqrtx) are in AP li...

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  7. If the non-zero numbers a,b,c are in AP and tan^-1a,tan^-1b,tan^-1c ar...

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  8. If a,b,c,d are distinct positive numbers in AP, then

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  9. If sum(r=1)^nr(r+1)(2r+3)=an^4+bn^3+cn^2+dn+e, then

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  10. The pth term Tp of HP is q(p+q) and qth term Tq is p(p+q) when pgt1,qg...

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  11. For a positive integer n let a(n)=1+1/2+1/3+1/4+.......+1/((2^n)-1) th...

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  12. A geometric progression of real number is such that the sum of its fir...

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  13. If the first and the (2n-1)^th term of an A.P,G.P anf H.P are equal an...

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  14. If a,b,c be in H.P prove that (1/a+1/b-1/c)(1/b+1/c-1/a)=4/(ac)-3/b^2

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  15. Which one of the following statements is correct ?

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  16. Let sinalpha,cosalpha, be the roots of the equation x^2-bx+c=0. Then w...

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  17. Which one of the following statements is correct ?

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  18. The sum V1+V2+.....Vn is

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  19. Tr is always

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  20. Which one of the following statements is correct ?

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