Statistics Probability Question

Question

4d. You are given a multiple choice test with 7 questions. Each question has 5 possible answers (a, b, c, d, or e). You know absolutely nothing about the subject matter, but know that you might select the correct answer by randomly guessing.  

Express, as a fraction, the probability of correctly answering all 7 questions correctly.

Answer 1

You have a 1/5 chance of getting each question right. Those odds don't change (each question is independent of the others), so to calculate the chances of getting all 7 right, we multiply the individual probabilities: (1/5)·(1/5)·(1/5)·(1/5)·(1/5)·(1/5)·(1/5) = 1/5⁷

(1/(78,125))? if my mental math is right.

We could just call the odds "ridiculously low," and leave it at that.