Q. What is the next number of the following sequence.
6,18,21,8,11,33,2,6,9,5,8,24,7,21...?

• 6*3 = 18 , 18 + 3 = 21
  8 + 3 = 11 , 11 * 3 = 33
  2*3 = 6 , 6 + 3 = 9
  5+3 = 8 , 8 * 3 = 24
  
  7*3 = 21 , 21 + 3 = x
  
  21 + 3 = 24 answer will be 24
• 11 years agoHelpfull: Yes(34) No(1)
• Series runs by *3,+3 and +3,*3 consecutively.
  6*3=18, 18+3=21
  8+3=11, 11*3=33
  2*6=6, 6+3=9
  5+3=8, 8*3=24
  similarly, 7*3=21, 21+3=24(required series number)
• 11 years agoHelpfull: Yes(9) No(1)
• 6*3=18 18+2=21
  8+3=11 11*3=33
  2*3=6 6+3=9
  5+3=8 8*3=24
  7*3=21 21+3=24 (combinations of + and * operations )
• 11 years agoHelpfull: Yes(4) No(2)
• 21-18=3
  33-11=20
  9-6=3
  24-8=16
  X-21=3
  X=24
• 11 years agoHelpfull: Yes(2) No(2)
• series is =3,*3 take alternatively
  so ans=10
• 11 years agoHelpfull: Yes(1) No(6)