In my current job I did a PR in the first week of joining. It was reviewed after exactly 2 years. I had to rewrite the whole PR because of the affected lines had changed. Of course I did not remember at all what is was about.
Maybe you meant getting a PR merged. Then 3 days seems possible depending on the approach.
At my current company, the team is small so approval process is quite fast and not too fussy.
Some PRs are faster but some are slower as well.