in a certain examination paper there are n questions ,FOr j=1,2,....n, there are 2^n-j students who answered j or more questions wrongly. If the total number of wrong answers is 4095, then the value of n is

• 2^n-1+2^n-2+.....+2^n-n=4095
  2^n(1/2+1/2^2+......+1/2^n)=4095
  2^n(1-1/2^n)=4095
  2^n-1=4095
  2^n=4096
  n=12.
• 2 years agoHelpfull: Yes(2) No(0)
• 2^n-1
  = 2¹²-1 = 4095
  
  Ans n= 12
• 2 years agoHelpfull: Yes(0) No(0)
• be put j=1
  so 2^n-j=4095
  2^n-1=4095
  2^n=4096
  n=12
• 1 year agoHelpfull: Yes(0) No(0)