Find the missing term in the following series: 5, 3, 12, 7, 26, 15, ?
a) 54
b) 27
c) 108
d) 31
e) None of these

• there are two patterns in this puzzle
  one is 5,5*2+2,12*2+2
  other one is 3,3*2+1,7*2+1,
  so as by first pattern the answer is 26*2+2=54
• 10 years agoHelpfull: Yes(17) No(0)
• 54
  
  5*2+2=12
  12*2+2=26
  26*2+2=54
• 10 years agoHelpfull: Yes(4) No(1)
• this is a combination of two series 1st is 5,12,26,.. and 2nd 3,7,15... at ? place now when look carefully now it is turn of first series outcome it is like 5+7=12, 12+14=26, 26+21=47 so ans(47)here none of these.
• 10 years agoHelpfull: Yes(4) No(0)
• there are 2 ways of it with 2 answers
  first: 5*2+2=12
  12*2+2=26
  26*2+2=54
  second: 12-5=7
  26-12=14
  47-26=21 such that the difference comes to be the multiple of 7.
  similarly the other pattern also follow the same with a difference of multiple of 4.
• 10 years agoHelpfull: Yes(3) No(1)
• 5*2+2=12
  3*2+1=7
  26*2+2=54
• 10 years agoHelpfull: Yes(2) No(1)
• 5*2=10+2=12
  12*2=24+2=26
  26*2=52+2=54
• 10 years agoHelpfull: Yes(2) No(2)
• consider altrnt terms 5,5*2+2,12*2+2,26*2+2..
  so 54
• 10 years agoHelpfull: Yes(1) No(1)
• multiply odd terms difference with 2 and add to the previous odd term
• 10 years agoHelpfull: Yes(0) No(0)
• alternate series
  5,12,26,54=(*2+2)=logic
  3,7,15logic(*2+1)
• 10 years agoHelpfull: Yes(0) No(0)
• 5,12,26,x are 1 series,(12-5)=7;(26-12)=14;(x-26)=28 ,so x=54
  3,7,15,... are 1 series
  
• 10 years agoHelpfull: Yes(0) No(0)
• Odd Position is 5,5*2+2,12*2+2...
  So ans is 54..26*2+2=54...
• 10 years agoHelpfull: Yes(0) No(0)
• 54 is my answer
  because (5*2)+1=12
  (12*2)+2=26
  (26*2)=54
• 4 years agoHelpfull: Yes(0) No(0)