Answer
$$\boxed{4.74*10^{−11}
}$$
Work Step by Step
The chance of doing a specific problem correctly by guessing is $1/4$ Then, the number of ways to choose which ones are correct is dictated by $_{30}C_n$ where n is the number of correct OR incorrect (it doesn't matter because they will add up to 30 either way.
$$_{30}C_{11}*(1/4)^{30}=\boxed{4.74*10^{−11}
}$$
