if i guess at five choice questions. each question has 5 anwsers to pick from. whats the probability that i l get three correct? tell me how u did it also thanks.

If $p$ is the probability of success and $N$ is the number of trials then the probability of exactly $k$ successes, where $0\le k\le N$, is $\binom{N}{k}p^k(1-p)^{N-k}$.