3, 22, 7, 45, 15,? , 31
a)91 b)151 c)90 d)5

• 2 series r dere n ans is 91..
  
• 13 years agoHelpfull: Yes(5) No(0)
• two series are there
  3,3*2+1=7,7*2+1=15 etc
  22,22*2+1=45,45*2+1=91 etc
  ans is 91
• 13 years agoHelpfull: Yes(5) No(0)
• there are two series =
  1 series -> 3 , 3+4=7 , 7+8=15 , 15+16=31
  2 series -> 22 , 22+23=45 , 45+46=91 ,
• 13 years agoHelpfull: Yes(2) No(0)
• 3,7,15,.......... 22,45,..45*2+1=91
• 9 years agoHelpfull: Yes(0) No(0)
• 91
  3*2=6+1=7...............................15*2=30+1=31.
  22*2=44+1.................................45*2=90+1=91
• 9 years agoHelpfull: Yes(0) No(0)
• even place nos: 22 22*2+1 45*2+1
  therefore: a)91
• 8 years agoHelpfull: Yes(0) No(0)