Question

Sam has nine flower pots, and want to display four of them on the front porch, in a row. (The order of the pots matters.) How many different displays are possible?

Answer 1

Permutations of 9 flower pots taken 4 at a time:

nPr = 9P4 = 3,024 - displays possible when order of flower pots matters.
I hope this helps
I at least think what this is asking.

Answer 2

Sam can choose any of the 9 pots for the first in the row, any of the remaining 8 for the second in the row, then any of the remaining 7, then any of the remaining 6. The total number of different displays is
  9*8*7*6 = 3024

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This is nPk = n!/(n-k)! where n=9 and k=4.