3, 5, 15, x, 51, 53,159,161
a)17 b)34 c)54 d)112

• ans is a..
  as in dis dere r 2 series
  15,51,159----- in dis series is 15,15*3+6,51*3+6
  x,53,161-----x*3+2,53*3+2 => x=17
• 12 years agoHelpfull: Yes(0) No(0)
• ans is 17...as there r pairs wid the difference of 2..leaving 3 if we see from 15 and x,then 51 and 53 then 159 and 161...all have d differnce 2...therefore x will be 17.
• 12 years agoHelpfull: Yes(0) No(0)