5, 9, 12, 18, 26, 36, 47, 72, _?
a) 75 b) 135 c) 100 d) 55

• Ans is 75
  5+(7*1)=12
  12+(7*2)=26
  26+(7*3)=47
  47+(7*4)=75
• 12 years agoHelpfull: Yes(13) No(2)
• ANSWER : 75
  
  SOLUTION :
  
  12-5=7
  26-12=14
  47-26=21
  so,
  47+28=75
• 12 years agoHelpfull: Yes(7) No(1)
• alternate series 5,12,26.47,.... and 9,18,36,72
  second one is getting double
  and first series 12-5=7, 26-12=14, 47-26=21
  therfore next difference is 28, so number is 47+28=75
• 12 years agoHelpfull: Yes(3) No(0)
• ANSWER : 75
  
  SOLUTION :
  
  12-5=7
  26-12=14
  47-26=21
  so,
  47+28=75
• 12 years agoHelpfull: Yes(2) No(1)
• ans is 75.
  reason:5+7=12+14=26+21=47+38=75
• 12 years agoHelpfull: Yes(1) No(3)
• 12-5=7 26-12= 14 ....x-47=28 x=75
• 12 years agoHelpfull: Yes(0) No(0)