Question

how many 3 letter permutations are possible for the letters S T U D Y H A R D

Answer 1

The formula to use is as follows:
\[nPr=\frac{n!}{(n-r)!}\]
Where the number of elements to select from is n = 9 letters, and r = 3 the number selected at a time

Answer 2

Which is 7x8x9