A new puzzle, my new supermarket

Question

I'm going to open a new supermarket in my town and decide to tell everybody about it, firstly I'm going to infrom four of my relatives within thirty minutes. and every one of those four relatives informes other four persons within thirty minutes.. etc..

how much time does it take so as the WHOLE PEOPLE IN THE WORLD know that I have a new supermarket?

Note : Consider the World Population : 5,702,224,175

Answer 1

30 minutes = 4 people

60 minutes = 16 people

30*x minutes = 4^x people

5702224175 = 4^x

log 5702224175 = x log 4

x = log 5702224175 / log 4 = 16.2

Therefore it will take around 16.2 * 30 minutes = 8 - 8.5 hours

Answer 2

in 9 hours

Answer 3

in eight hours, around 4.3 billion people have already heard about your new supermarket ...

in the next 30 minutes, all people, living and dead would have heard it ...

Answer 4

these many hours 712778021.875.

Answer 5

This sounds like the whole rabbit thing, their rate of reproducing. What's that called? Oh well. Besides, you can't tell everyone. Too many dead.