In one town 61 percent of adults have health insurance What is the probability that 8 adults selected at random from the town all have health insurance?

.61 ^ 8 = .0191707... = 1.92%

And an informal proof/explanation:

P(A and B) = P(A) * P(B),

which means the probability of A and B = Probability of A times the probability of B.

P(1st person and 2nd person) = P(1st person) * P(2nd person)

P(1st person and 2nd person and 3rd person) = P(1st person) * P(2nd person) * P(3rd person)

...

P(1st person) = P(2nd person) = ... = P(8th person)

P(1st-8th people) = P(1st) * P(2nd) * ... * P(8th) = P(1st person) ^ 8

.61 ^ 8 = .0191707... = 1.92%