Question 664071
Use the binomial probability distribution formula P(X = k) = (n C k)*(p)^(k)*(1-p)^(n-k)


In this case, k = 3, n = 4 and p = 0.7


P(X = k) = (n C k)*(p)^(k)*(1-p)^(n-k)

P(X = 3) = (4 C 3)*(0.7)^(3)*(1-0.7)^(4-3)

P(X = 3) = (4 C 3)*(0.7)^(3)*(0.3)^(4-3)

P(X = 3) = (4)*(0.7)^(3)*(0.3)^1

P(X = 3) = (4)*(0.343)*(0.3)

P(X = 3) = 0.4116


So the probability is 0.4116, which is a 41.16% chance.