A "combination" lock is opened with the correct sequence of three numbers between 1 and 40 inclusive. (A number can be used more than once.) What is the probability of guessing those three numbers and...

Extracted text: A "combination" lock is opened with the correct sequence of three numbers between 1 and 40 inclusive. (A number can be used more than once.) What is the probability of guessing those three numbers and opening the lock with the first try? P(first guess opens lock) = (Type an integer or simplified fraction.)