Answer:
Step-by-step explanation:
Out of the 7 coins, one is fake and has heads on both sides. So, fake coin on toss coin will always turns up to be head.
Therefore, to obtain the probability of exactly 5 heads is:
probability of getting exactly 4 heads from the 6 fair coins
Probability of getting heads, p =
Probability of not getting head, q = 1 - p =
Now, by Binomial distribution with:
p = = 0.5
q = = 0.5
n = 6
P(X = r) =
P(X = 4) =
P(X = 4) =
P(X = 4) =
On solving the above eqn, we get:
P(X = 4) = 0.2344
Therefore, the probability of getting exactly 5 heads is 0.2344