create a similar cipher to Caeser's that operates on pairs of consecutive letters

[spo0ofer]

I have home work and I would like to be ready in 1 day so I will be very happy if you help me .
My exersices are:
1. To create a similar cipher to Caeser's that operateson pairs of consecutive letters
2. To calculate the average tries needed to get 4 with a six-sided dice.
3. How many tries are needed on average to get all the numbers1 to "n" at least once when a fair "n"-sided dice is used.

I have to finish with this at monday I mean the deadline is then I will do my best to do 2 exersice I know its not hard for mathematics ,
Thank you so much in advance
All the best to everyone

 

[stapel]

I have home work and I would like to be ready in 1 day so I will be very happy if you help me

We'll be glad to help but, as you read in the "Read Before Posting" announcement, we don't "do" students' work for them, nor do we give out the answers; first, we need to see the student's efforts.

1. Create a cipher, similar to Caesar's, that operates on pairs of consecutive letters.

By "Caesar's cipher", is your book referring to a simple shifted-letter substitution cipher (here), where each letter in the Latin alphabet is shifted a certain (fixed) number of places away?

2. Calculate the average tries needed to roll a 4 using a fair six-sided die numbered 1, 2, 3, 4, 5, and 6.

You've done some basic research, such as here. Where are you stuck?

3. How many rolls are needed, on average, to roll all the numbers 1 through "n" at least once, when a fair "n"-sided die is used?

I have to finish with this by Monday...

Then you'd better get busy! Please reply with a clear listing of your thoughts and efforts so far, showing all of your steps, up to where you get stuck. Thank you!