Question

Use the 'Permutations' formula to evaluate the expression P(27,3)

Answer 1

The permutation formula is given as:

$P(n,k)=\frac{n!}{(n-k)!}$

In this case n=27 and k=3; plugging the values in the formula we have:

$P(27,3)=\frac{27!}{(27-3)!}=\frac{27!}{24!}=\frac{27\cdot26\cdot25\cdot24!}{24!}=27\cdot26\cdot25=17550$

Therefore, we have that P(27,3)=17550