Sally has 6 red flags, 5 green flags, and 4 white flags. How many 15 -flag signals can she run up a flag pole?

There are ten spots where you can put a white flag. 10

There are nine spots where you can put a second white flag. 9

There are eight spots where you can put a green flag. 8

Likewise - - - 7

Likewise - - - 6

There is only one way to fill the remaining spots with red flags.

Total: 10 x 9 x 8 x 7 x 6 = 30,240