# In an examination a candidate has to pass in each of the four subjects. In how many ways he can fail?

$\begin{array}{1 1} 16 \\ 14 \\ 24 \\ 15 \end{array}$

No. of ways in which one can pass or fail in the examination = $2^4=16$
To pass one has to pass in all the subjects.= 1 way
$\therefore$ The no. of ways in which one can fail = 16-1=15 ways.