When, where, why and who decided to divide the date of day and night consisting of 24 hours each of 60 minutes of 60 seconds each instead of the prevailing decimal system?

This article might have the explanations you’re looking for. It’s also quite an interesting read!

@Virender I’m delighted to leap second onto this subject with the suggestion that you might also want to look at the bigger picture viz. how come there’s seven days in a week.

Seven days in a week is easy, it’s from observing phases of the moon.

Read this as well apparently it has something to do with your fingers.

24 hours- Egyptians divided the time into 10 hours for night and 10 hours for day using shadow clocks and then added 2 hours. 1 hour for twilight and 1 for night.
60 minutes- the Greeks divided the 24 hours using their base 60 system. So they divided each hour into 60 mins and each minute into 60 seconds. Not sure why they chose base 60

That still leaves the question of why 12, 24, 60 and 360 were chosen. These are what mathematicians call highly composite numbers, meaning they can each be divided evenly in more ways than any smaller number That makes them convenient units of measure. For example, 12 is divisible by 2, 3 4 and 6 in addition to 1 and 12. For this reason, some people think we should switch to the duodecimal system. 360 is divisible by 24 numbers.

12 was chosen because of your fingers according to the article I linked

Base 60 was from the Babylonian number system. You are right about the Egyptian origin of 12 and 24 hours. It is still the case that 12 and 24 are highly composite numbers.

60 is evenly divisible by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30. That makes it easy to split up time into useful chunks.