how long does it take to make a website

It depends on the website you're trying to build.

Think of it this way 'how long does it take to cook dinner'.

If dinner is a microwave meal - it takes about 5 minutes If Dinner is a multi course meal for a dozen people it takes hours.

The more basic (and non dynamic) your web site it - the quicker it'll be.

Building a one page HTML site with no styling probably takes no more than 20-30 minutes depending on how fast you type and if you know in your head how you want it to look.

Building a dynamic e-commerce store from scratch with responsive design and lots of cute web 2.0 CSS and Ajax tricks that is run through test driven development, agilely, and refactored, is going to take a very long time especially on your own

That's a tough question to answer. I can write up a little code, and throw something up in a few minutes that says 'Hello World'. For a 'real' website, with actual content, well, the more complicated the website, the longer it'll take to create and publish.

Depending on your skill, you could put a decent but simple website up in a day or two, especially if you use a framework like Bootstrap. Large websites can take a lot of time, because there is a lot that goes into making them. Typically for something large, there is a team of people working on them, some doing front end development, some back-end development, and others who just do designing.