A coin is tossed 10 times. How many different sequences of tosses could there have been, if at least $3$ of the tosses were heads?
(10 C 3) + ∑ (n, 4, 10, (10 C n))==120 + 848 ==968 sequences of tosses.
210 - 10 C 2 - 10 C 1 - 10 C 0 = 1024 - 45 -10 -1 = 968 possible sequences
+36916 
