Question 1197528
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Ignoring one extra stray character "5" in the statement of the problem, it seems clear that the experiment involves tossing 5 fair coins, one of which has heads on both sides.<br>
So that coin will definitely come up heads.  So to find the probability that the result is exactly 2 heads, we need only find the probability that exactly 1 of the other 4 coins comes up heads.  Since all the coins are fair, that is an easy calculation.<br>
The probability of either heads or tails on each of the 4 coins is 1/2; and we need to choose 1 of the 4 coins to be the one that comes up heads:<br>
P(exactly 2 heads) = {{{C(4,1)*(1/2)^4=C(4,1)/2^4=4/16=1/4}}}<br>