i'm a little confused here,
four different colored flags can be hung in a row to make coded signals. How many flags can be made if a signal consists of the display of one or more flags?

I don't know how the answer became 64.

Question

i'm a little confused here, 
four different colored flags can be hung in a row to make coded signals. How many flags can be made if a signal consists of the display of one or more flags?

I don't know how the answer became 64.

anonymous · Answer

one flag, 4 ways
two flags $4\times 3=12$ ways 
three flags $4\times 3\times 2=24$ ways 
four flags ...

anonymous · Answer

i assume it meant "how many SIGNALS...." not how many flags...

anonymous · Answer

i think so.

anonymous · Answer

i used permutation and i got 64.

anonymous · Answer

add em up 
$$4+12+24+24$$

anonymous · Answer

ok, thank you.