What is the missing number in the series?
4,9,20,43,90??

• ans is 185
  4*2+1=9
  9*2+2=20
  20*2+3=43
  43*2+4=90
  similarly 90*2+5=185
• 10 years agoHelpfull: Yes(3) No(1)
• 9-4=5
  20-9=11 so 11-5=6
  43-20=23 23-11=12
  90-43=47 then 47-23=24
  
  so next no. will be 48 as it is multiple of previous term
  so ANSWER IS 138
  
• 11 years agoHelpfull: Yes(1) No(6)