Probability Sampling with replacement

A box contains tickets marked 1,2,...n. A ticket is drawn at random from tehe box. Then this ticket is replaced in the box and a second ticket is drawn at random. Find the probabilities of the following events:

The first ticket drawn is number 1 and the scond ticket is number 2.

The numbers on the two tickets are consectuive integers, meaning the first number drawn is one less than the second number drawn.

The second number drawn is bigger than the first number drawn.

I understand the first part of it. The first ticket probability is 1/n and second ticket probability is 1/n so it's 1/n^2.

The second one has the first part as 1/n and the second part as (n-1)/n so it's (n-1)/n^2.

I don't understand the third scenario. The answer as shown is (1-1/n)/2?

Re: Probability Sampling with replacement

Hi, I have a similar question.

A random sample n = 3 is selected from N with replacement.

I do not understand why the probability of having , two distinct

units is P = 3*(N-1)/(N^2), and three distinct units is P = (N -1)(N -2)/N^2

Thanks