Question 69034
For a single keystroke, there are 2 possible
(.),(-)
For a double keystroke, there are 4 possible
(..)
(--)
(.-)
(-.)
For 3 keystrokes, ther are 8 possible
(...)
(..-)
(.-.)
(-..)
(---)
(--.)
(-.-)
(.--)
And for 4 keystrokes, there are 16 possible
Without going through all the combinations, there
are 2 choices for the 1st, 2 for the 2nd, 2 for the 3rd, and 2 for the 4th
{{{2*2*2*2 = 16}}}
To sum the total possible characters
{{{2 + 4 + 8 + 16 = 30}}} answer