NIMCET 2019 Question Paper with solutions

For n independent boolean variables, each taking one particular boolean value, there are $2^{\mathit{n}}$ different possible combinations. A boolean function has to assign one boolean value to each one of these combinations. This brings the number of different possible boolean functions of n variables to a total of $2^{2^{\mathit{n}}}$
When $\mathit{n}=1$ we have only one boolean variable that can take either boolean value, so we have only $2^1=2$ different cases. This produces $2^2=4$ boolean functions of one boolean variable.