Question 1176487
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            At most  2  flags means   2   or  1   or  0   (if consider the absence of flags as a special signal).



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So, you can display 5 signals, showing any one single separate flag of five flags that you have.


Next, you can display 5*4 = 20 signals, showing ordered pairs of distinct flags.


So, you can display, in total, 5 + 20 = 25 signals using 1 or 2 flags.


If there is an agreement that the absence of flags is a special signal, too, then you can display 25 + 1 = 26 signals.
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Solved, &nbsp;answered and explained.



Notice that &nbsp;26 &nbsp;is exactly the number of letters in &nbsp;English alphabet (!)