How many 6-permutations of  have their digits listed in increasing order? (where  is the set of positive intergers <= 15)
I am thinking that this would be just .
Consider 3-permutations of  in increasing order...
123 124 125 134 135 145 234 235 245 345 which has 10 different members which is .
Would this be correct?
The Hint in the back of the text says:
Once you know which six numbers are in the permutations, how many ways are there to put them in increasing order?
As always you are a gentleman and a scholar! Thank you again.