Insert the missing number
9, 12, 11, 14, 13, ..., 15
A. 12 B. 16
C. 10 D. 17

• Ans = B)16
  Exp = The sequence is consider into two series..
  First series(odd) starting with 9 and increasing 2 as follows.
  Second series(even) starting with 12 and increasing with 2 as follows.
  i.e. 9 = 9 (odd)
  12 = 12(even)
  
  9 + 2 = 11(odd series)
  12 + 2 = 14(even series)
  11 + 2 = 13(odd series)
  14 + 2 = 16(even series)........
  
  $ Vignesh (India, TamilNadu) $
• 12 years agoHelpfull: Yes(4) No(0)
• +3 & -1 are added to alternative numbers
  9+3=12,12-1=11,11+3=14,14-1=13,13+3=16,16-1=15
• 12 years agoHelpfull: Yes(1) No(0)
• ans:B the series difference is 3,-1,3,-1...so at 13 add 3 its 16.
• 12 years agoHelpfull: Yes(1) No(0)
• ans is 16 because series comes as adding 3 and subtracting by 1
• 11 years agoHelpfull: Yes(1) No(0)
• Ans. B. 16
  
  Have two different series
  1) 9, 11, 13, 15...
  2) 12, 14,.... 16 is the Next Number
• 12 years agoHelpfull: Yes(0) No(2)
• 9+11+13------------
  12+14+16-----------
  9+12+11+14+13+16+15+
• 12 years agoHelpfull: Yes(0) No(0)
• ans : b 16
  
  9, 12, 11, 14, 13, .16., 15
  3 -1 3 -1 3 -1
• 12 years agoHelpfull: Yes(0) No(1)