(a)  The word "JasmineOrtz" has 11 letters, and they all are different.


     So, when the order of selection does matter, you may 

         - put any of 11 letters in the first position, when you select; (it gives you 11 options)

         - put any other of remaining 10 letter in the second position ((it gives you 10 options)

         - put any other of remaining 9 letter in the second position ((it gives you 9 options)
.


    Therefore, you have 11*10*9 = 990 options (permutation) in all, in this case.



(b)  If the order does not matter, you should divide this number of 990 by 6,

     because any set of 3 letters has 3! = 1*2*3 = 6 permutations.

     
     So, the answer in this case is  990/6 = 165.