Question

Hello all, I am having a bit of a problem on my probability homework.

9. A Blum-Blum-Shub random number generator produces a string of random bits. A bit is random if the probability of it being 0 or 1 is . Let’s assume a random bit number is generated. (14 points)
a. What is the probability that a string with all 1’s is generated.
b. What is the probability that a string with 1’s is generated.

The formula I am using is b(x;n,p) = nCx * p^x * (1-p)^n-x

Is this the correct formula?