A series is formed such that next num is 1+ sum of all previous nums. If 10th term of series is 1280, than what is 1st term.
a)1
B)4
C)5
D)None

Ans: 4

• let the firt no be x,
  second no is 1+x then 1+x+x+1 and so on
  series is x,x+1,2(x+1),4(x+1),8(x+1), upto 10th term
  10th term is 128(1+x) =1280 => x=4
• 9 years agoHelpfull: Yes(4) No(6)
• let the firt no be x,
  second no is 1+x then 1+x+x+1 and so on
  series is x,x+1,2(x+1),4(x+1),8(x+1), upto 10th term
  10th term is 256(x+1)=1280=>x=4
• 9 years agoHelpfull: Yes(3) No(0)
• can anyone tell me what was the que and answer of question asked in tcs off campus like....
  A man play 6 game and 3 game win and 3 game lost...... ?
• 9 years agoHelpfull: Yes(0) No(1)
• 10 th term should be 224(X+1)=1280
  
• 8 years agoHelpfull: Yes(0) No(0)
• let us assume the first number be x,
  second number be x+1,
  third number be 1+x+x+1=2x+2=2(x+1),
  fourth number be 4(x+1) and so on...
  The series is x,x +1,2(x+1),4(x+1).....
  10th term will be 256(x+1)=1280
  x+1=1280/256=5
  x=4.
• 6 years agoHelpfull: Yes(0) No(0)