Hi Can someone plz help me with these 2 questions. Its important.

Q1) The number 1,2....n are arranged in random order. Find the probability that the digits (a) 1 and 2, (b) 1,2 and 3, appear as neighbors in the order named.

Q2) If n balls are placed at random into n cells, find the probability that exactly one cell remains empty.

Thank you