Im stuck at this parts

(d) If a 5-digit number is chosen randomly, what is the probability that all its digits are primes? (e) How many 6-digit numbers are there with no repeated digits? (f) If a 6-digit number is chosen randomly, what is the probability that it has no repeated digits? Problem 2 (permutations) (a) How many possibilities are there to line up 5 persons in a queue? (b) Suppose there are 2000 spectators in a soccer-stadium. During halftime, a queue of 5 spectators forms in front of a coffee shop. How many possibilities are there for such a queue to form from the spectators? (c) A salesman travels through 10 cities. He starts at a certain city, visits each city exactly once, and then returns to the start city. For instance, if the cites are A, B, C. . .., I, J, one possible tour is A - C - D - B-E-F-G-H -I-J- A. How many possible tours are there? Note that two tours are considered equal if they visit the cities in the same order (the start city does not matter). For instance, the tour A - C - D - B - E - F-G- H- I - J - A is equal to