What would be the missing number in the series: 1, 20, 266, 675?

• the series is 1,20,x,266,675
  taking the adjacent we have
  20-1,x-20,266-x,675-266
  so we will get
  19,x-20,266-x,409
  again,
  x-20-19,266-x-x+20,409-266+x
  we will get
  x-39,286-2x,143+x
  again
  286-2x-x+39,143+x-286+2x
  we will get
  325-3x,3x-143
  again,
  3x-143-325+3x
  we will get
  6x- 468
  then equate it to 0
  that is
  6x-468=0
  6x=468
  x=468/6
  x=78
  so,
  the series is
  1,20,78,266,675
  
• 7 years agoHelpfull: Yes(4) No(0)
• 1,20,x,266,675
  > 20-1,x-20,266-x,675-266.
  >again doing the same upto
  >325-3x, -143+3x.
  >we get 6x-486 equate it with zero.
  > 6x-486 = 0
  >x = 78.
• 8 years agoHelpfull: Yes(2) No(8)
• pls descibe in easily way !!
• 8 years agoHelpfull: Yes(2) No(0)
• yaar question pura hai ya nhi
• 8 years agoHelpfull: Yes(0) No(3)