4,12,6,18,9,21,....... what is the next no. in the sequence.?

• 13.
  Let it have two series.
  1st series = 4,6,9,??
  2nd series = 12,18,21...
  2nd series increasing like +6,+3,....
  In this, 1st series increasing as +2,+3,+4 and so on.
  i.e., 4 +2 = 6
  6 +3 = 9
  9 +4 = 13.
  So, answer is 13..
  Final sequence = 4,12,6,18,9,21,13.
• 13 years agoHelpfull: Yes(13) No(4)
• I think there is mistake in copy paste of puzzle from daily puzzle dtd 30.01.12.pls check carefully.
• 13 years agoHelpfull: Yes(3) No(3)
• 4*12/8=6
  12*6/4=18
  18*6/(8+4)=9
  18*9/6=27
  9*21/(8+4+6)=13.5
  ans.
• 13 years agoHelpfull: Yes(3) No(5)
• think some mistake in question bcoz it begins with 4*3=12 then 12/2=6 then 6*3=18 then 18/2=9 so it should be 9*3=27 27/2=13.5
• 13 years agoHelpfull: Yes(2) No(3)
• [Naeem Ahamad]
  4*12/8=6
  12*6/4=18
  18*6/(8+4)=9
  18*9/6=27
  9*21/(8+4+6)=13.5
  ans.
• 13 years agoHelpfull: Yes(2) No(0)
• odd position numbers are increased by 1,2,3. So the Answer is 13
• 13 years agoHelpfull: Yes(2) No(1)
• 13.
  Let it have two series.
  1st series = 4,6,9,??
  2nd series = 12,18,21...
  2nd series increasing like +6,+3,....
  In this, 1st series increasing as +2,+3,+4 and so on.
  i.e., 4 +2 = 6
  6 +3 = 9
  9 +4 = 13.
  So, answer is 13..
  Final sequence = 4,12,6,18,9,21,13.
• 13 years agoHelpfull: Yes(1) No(1)
• But my logic is correct only knoww?????
• 13 years agoHelpfull: Yes(0) No(4)
• it will be 13
• 13 years agoHelpfull: Yes(0) No(3)
• 4*3=12
  6*3=18
  4,6,9,13
  answer is 13
• 12 years agoHelpfull: Yes(0) No(1)
• given as, 4,12,6,18,9,21.....
  note that the number is alternatively increase and decrease...
  so take the middle number 9, 9+9=18,18-12=6,6+6=12,12-8=4
  and also then, 18-9=9,9+12=21, 21-6=15,.. lets arrange them to understand clearly,
  21-6=15,
  9+12=21,
  18-9=9,
  9+9=18,
  18-12=6,
  6+6=12,
  12-8=4..
  so ans is 15.....
• 11 years agoHelpfull: Yes(0) No(0)
• 13.
  Let it have two series.
  1st series = 4,6,9,??
  2nd series = 12,18,21...
  2nd series increasing like +6,+3,....
  In this, 1st series increasing as +2,+3,+4 and so on.
  i.e., 4 +2 = 6
  6 +3 = 9
  9 +4 = 13.
  So, answer is 13..
  Final sequence = 4,12,6,18,9,21,13.
• 9 years agoHelpfull: Yes(0) No(0)