1. Who first started tracking time as we know it - 60 sec=1 min,60 min=1 hour,24 hours=1 day,365 days=1 year?

Question

2. What is the mathematics/basics behind this? Why didn't the people who started tracking time come up with something like this - 40 sec = 1 min, 50 mins = 1 hour, 30 hours = 1 day, 365 days = 1 year?

3. I can understand how 365 days came, but why was 1 day made to be 24 hours only and not say 30 hours (which will result in less minutes in an hour). There should be some reason behind this.

Answer 1

Twelve is a cool number because you can divide it evenly into halves and thirds and quarters. It's also about the number of times the moon goes around in one year, hence twelve months in year. So the Sumerians divided the day into 12 parts, and also the night into 12 parts. Sixty is also a good number for dividing things up, because it's good for halves, thirds, quarters, fifths, and sixths. Also 10ths and 12ths and 15ths and 20ths, etc, but it's not a ridiculously large number. You can divide an hour into 60 parts, and if you want a finer division you divide it by 60 a second time (which is why we call them "seconds"). That's the way the Sumerians did it, and I guess it caught on.

Answer 2

I suppose the ancient civilisations have done this.
It seems that he first system of calculus used was with base 6 instead base 10 as now. The reminder are number divisible by 3

Answer 3

Sumerians (Iraq). Some archaeologists say their elite was mostly six-fingered persons