First...we have to agree on what "execute" means. The definition below was taken off on the internet:

Definition of Execute

Noun

1.    To complete, and give effect or validity to, a legal document, decree, law, or judicial sentence.

2.    Fulfilling legal requirements of a contract or other instrument by signing or sealing.

So...you can see that, once a contract is written, it can take only a short time to "execute" the contract.

Yet, I do not think what you wrote is really what you want to ask.

If you are asking how long it take to complete a real estate transaction, that is not a questions that can be precisely answered.

Some transactions, as in a cash purchase, can move to close in days.

Others, due to inspections, negotiations, financing, escrow processing and other possible delays can easily take 30 days or, in some cases, much longer.

Many contracts are written with a close of approximate 30 days in mind and work out satisfactorily.

Your question is pretty vague. I'll try to translate it...

If you mean when one is written in relation to getting a new buyer, it all depends on the buyer and the market. 60-90 months is average right now.

If you are asking how long a typical escrow is, 21-45 days.

the rule of "if you ask better questions, you get better answers" applies

Definitions matter. Specifics too.

Depends on the quality of the product.
The PROM Queen goes in a week.
The beige product a few weeks.
The bargain product a few days.
If the listing agent is not good at assessing buyer intentions and qualifications, rinse and repeat may be necessary.
There is another 'quality' that affects time. That would be the 'curve busting' I'm in no hurry to sell homeowner. That always creates an environment of interest and agility.

By execution, meaning all parties agree and sign, i like it done right away. no more than 30 minutes. I call the parties, tell them to check their email and have them esign 

From Offer to Execution (Closing), 30 to 45 days is average here in NC & SC.

 Execution is when all parties have signed it.

Are you referring to Closing?   From the date of Execution, to the day when the Seller gets paid, and the Buyer gets the Deed and the Keys?

    Cash = 3 to 14 days, depending upon if the Buyer wants Title Insurance,  Survey, Inspections, etc.

   Conventional Loan = we ballpark 30 days; I just did one in 15 days (local bank, portfolio loan).

   FHA/VA and USDA Rural = 45 days+ if you are lucky.

    Owner/Seller Financing (not common) = 10 to 15 days.

    Options, Lease with Option to Buy, etc.  =  See an Attorney in your area

6 to 9 months, but I'm a builder.

When everybodys "want to" is triggered...records are broken. 

11 great answres and your question was covered.

I wish you all the best with your real estate studies. 

30 - 60 days from offer to closing in this area

Answers were given. 

Best of luck with the school.