Hello i had new 6 questions but i cant solve this two any help will be appreciated thanks
Question 4 (15%)
A-) Give an one-line proof for $ n^r \ge C(n+r-1,r) $
[Hint: direct proof]
B-) What is the implication on the number of r-permutations and that of r-combinations with repetition? Give one-line description.
Question 6 (10%)
A computer network consists of six computers. Each computer is directly connected to at least one of the other computers. Show that there are at least two computers in the network that are directly connected to the same number of other computers.
Answer should be no more than 3 lines.