John draws a regular five pointed star in the sand, and at each of the 5 outward-pointing points and 5 inward-pointing points he places one of ten different sea shells. How many ways can he place the shells, if reflections and rotations of an arrangement are considered equivalent?
Answer is not 3628800
+658 Plan:
Treat the star like a circle
In a circle counting problem, \(n\) people can be seated in \((n-1)!\) ways.
Solve:
\((10-1)!=9!\)
\(\boxed{362880}\)
+2095 AnExtremelyLongName is correct! You can also check out the answer here:
+658 I used to do AoPS forums, but it's more of chatting than actual problem solving.
