What is the next number of the following sequence
9, 3, 6, 21, 9, 12, 33, 15, ...?

• 9-3=6
  21-9=12
  33-15=18 ANS
• 10 years agoHelpfull: Yes(24) No(5)
• Look upon the series carefully
  9,3, 6,21,9, 12,33,15
  
  1st no - 2nd no. = 3rd no (it is the first multiple of 6)
  9 - 3 = 6
  
  4th no - 5th no = 6th no (it is the second multiple of 6)
  21 - 9 = 12
  
  similarly
  7th no - 8th no = 9th no.(it will be 3rd multiple of 6)
  33 - 15 = __
  so answer will be 18
• 10 years agoHelpfull: Yes(14) No(2)
• 6+3=9
  9+12=21
  then
  15+18=33
  so ans is 18
• 10 years agoHelpfull: Yes(3) No(1)
• 9,3,6,21,9,12,33,15,x
  9=3+6
  21=9+12
  33=15+x
  => x=18
• 10 years agoHelpfull: Yes(1) No(1)
• (9,3,6),(21,9.12),(33,15,?)
  3*1=3
  3*2=6
  (3+6)=9
  Similarly,3*3=9
  3*4=12
  (9+12)=21
  So, 3*5=15
  3*6=18
  (15+18)=33
  So ans is 18
• 10 years agoHelpfull: Yes(1) No(0)
• 9,3,6,21,9,12,33,15
  here we are using method to get a solution is
  substract 2nd number from 1st number inorder to get 3rd number i.e: 9-3=6
  simailarly 21-6=9
  finally 33-15=18
  ANS:18 CORRECT
• 10 years agoHelpfull: Yes(0) No(2)
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• 10 years agoHelpfull: Yes(0) No(2)
• 9-3=6
  21-9=12
  33-15=18
• 10 years agoHelpfull: Yes(0) No(2)
• answer 18
  3+6=9
  9+12=21
  18+15=33
• 10 years agoHelpfull: Yes(0) No(2)
• 18 is the next no. of the given sequence...coz
  taking 3 no at once first_no = second_no. + third_no.
  e.g. 9 = 3 +6
  21= 9+ 12
  33= 15+ 18
• 10 years agoHelpfull: Yes(0) No(2)
• 18
  dividing the numbers by 3 we get the series as
  3,2,1,7,3,4,33,15...
  
  we can see that 3-2=1,7-3=4,11-5=6
  so multiply 6*3=18
• 9 years agoHelpfull: Yes(0) No(1)
• ans=18
  exp.
  9-6=3
  21-12=9
  33-x=15
  x=18
• 9 years agoHelpfull: Yes(0) No(1)
• 6+3=9
  9+12=21
  15+x=33
  x=7.
• 9 years agoHelpfull: Yes(0) No(1)
• 9, 3, 6, 21, 9, 12, 33, 15,x
  9-3=6
  21-9=12
  33-15=18(Ans)
  
• 9 years agoHelpfull: Yes(0) No(0)
• (9-6=3)(21-12=9)
  33-48=15..........ans is 48
  
• 9 years agoHelpfull: Yes(0) No(2)