Answer
$8.67362\cdot10^{-19}$
Work Step by Step
The chance of doing a specific problem correctly by guessing is $0.25$. Then using the binomial probability distribution, the probability of having $30$ correct is: $_{30}C_{30}(0.25)^{30}(0.75)^{0}=8.67362\cdot10^{-19}$