I have shown in the case of Joseph and his brothers that 400 years is a quite suficient amount of time to reach a population of 600,000 men even if the fertility rate was as low as 4 children born to each women. Since we do not have accurate data on how many children die in backward countries before they reach adulthood I used the fertility rate of 4 (extremely conservative) to take this into account.
The case of the Flood survivors differs in that the lifespans were much longer before and after the Flood and only became reduced after hundreds of years.
Thus the fertility rate was undoubtedly much higher in first 100 or 200 years after the Flood.
God told Noah and the survivors to reproduce and fill the Earth, which they did.
I gave one illustration of many children could be born to one women: 69 in only 40 years (multiple births). Imagine how many could have been born if the lifespan after the Flood was 10 times longer !!!!
Since most Biblical historians believe Peleg was the instigator of the Tower project I used that in my example.
