in a test  there were n questions. in the test  2^{n - i} students gave wrong answers to  i  questions where i = 1,2,3...........n . if the total no. of wrong answers given is 2047 . then n is

total no. of wrong ans are

i.e., 2^n[1-(.5)^n]1-0.5

i.e.,

so =2047

so n=11

no one here

First line:I m assuming there is only 1 question ...so 2^1-1 students will get 1 question wrong ..which gives 1 question wrong

Secong line:Let there be 2 questions ...2^2-1 students get 1 questin wrong ., 2^2-2 students get 2 questions wrong ..thus 3 questions totally wrong ..

This way if we see ..in general ..for n questions ..there are 2ⁿ -1 wrong answers ..