Let #A = {a_1,...,a_10}# be the event of tossing a coin 10 times and landing on tails then we know that
#p(A) = p(a_1 ^^ a_2 ^^ ...^^a_10) = p(a_1)p( a_2)...p(a_10) # if they are mutually exclusive, which they are. the probability of landing on tails is #1/2# which leads to