Question 1093146
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<pre>
4            signals if to use 1 flag only,    plus

4*3     = 12 signals if to use 2 flags only,   plus

4*3*2   = 24 signals if to use 3 flags only,   plus

4*3*2*1 = 24 signals if to use all 4 flags.


In all, 4 + 12 + 24 + 24 = 64 signals.


<U>Answer</U>.  64 signals.
</pre>

Solved.