sum of 52 terms of the series 1,6,7,13..

• 1+6+7+13+20+.....up to 52 terms
  =1+6+(6+1)+(6+6+1)+(6+6+6+1+1)+....+[(6+6+...upto 50 terms)+(1+1+....+up to 49 terms)]
  A.P series from 3rd term....6[1+2+...+50]=6*25*51
  A.P series from 4th term.... [1+2+....+49]=49*25
  and the rest 1+6+1=8
  so, total of above series=6*25*51+49*25+8=8883
  
• 11 years agoHelpfull: Yes(13) No(14)
• Consist of two A.P. series
  1,7,13.. and 6,13,20 with common difference of 6 and 7 respectively.
  So, sum of 1st series 1974 as last term i.e., 26th term is 151
  sum of 2nd series 2418 as last term 187.
  so sum of 52 terms 2418+1974=4394
• 11 years agoHelpfull: Yes(4) No(21)
• @shirsedu ghosh your logic is not right.
• 11 years agoHelpfull: Yes(4) No(1)
• Its a fibonacci series
  
• 11 years agoHelpfull: Yes(4) No(3)
• is there any formula to calculate sum of Fibonacci series?
• 11 years agoHelpfull: Yes(3) No(3)
• find nth term which is summ of n-1th and n-2 term
  Tn=n-1+n-2=2n-3
  use summation and find ans is 2652
• 11 years agoHelpfull: Yes(1) No(0)
• @subham kumar i admit. Can you help me out?
• 11 years agoHelpfull: Yes(0) No(1)
• can sum1 pls xplain ds??
• 11 years agoHelpfull: Yes(0) No(0)
• 5004
  1+7+...
  
• 11 years agoHelpfull: Yes(0) No(0)
• ans: 4403
  It can be broken into to A.P series
  A.P 1= 1+7+13....
  A.P 2= 6+13+...
  COMMON DIFFERENCE= (7-1)=6 in A.P 1
  =(13-6)=7 in A.P 2
  no of terms in A.P 1 AND 2=(52/2)=26
  SO, By formula s=n/2(2a+(n-1)d)
  we get-
  for A.P 1=1976
  for A.P 2=2431
  adding both=4403
• 11 years agoHelpfull: Yes(0) No(0)