solve the series 3 12 7 26 15 -?

• ans
  wil be54
• 13 years agoHelpfull: Yes(1) No(1)
• consider two series.one series is:3 7 15.another one is:12 26.
  in 1st series:7-3=4 and 15-7=8.
  in 2nd series:26-12=14 and 54-26=28.
  so the ans will be 54.
  
• 12 years agoHelpfull: Yes(1) No(0)
• the series is like
  3,12,3*2+1,12*2,+2,15,15*2+3
  so 15*2+3=33
• 12 years agoHelpfull: Yes(1) No(3)
• ans is 54
  there r two series
  3 7 15
  which is
  3*2+1=7 7*2+1=15 15*2+1=31.....
  12 26 ?
  12*2+2=26 26*2+2=54
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• 12 years agoHelpfull: Yes(1) No(2)
• sixth term will be 54 and seventh term will be 31 as there are 2 series running alternatively 2n+1,2n+2.
  so ,26*2+2=54 and 2*15+1=31.
• 4 years agoHelpfull: Yes(0) No(0)