math problem...please help?

a man has 12 coins that consist of 3 pennies, 4 nickels, and 5 dimes/ How many distinct arrangements of the coins can he make if he lays the coins in a row one at a time?

jgoulden2009-02-26T14:12:16Z

Favorite Answer

We assume that like coins are indistinguishable. There are 12! possible combinations, but some have identical appearance, so the number of combinations is actually

12! / ( 3! ) ( 4! ) ( 5! ) = 27,720