Isn't This A Clue That People Lived For 1000 Year Of Age During Prophet Nuh?
We have no way to know how long people generally lived during those days. We don’t even know what time period is that of prophet Nuh AS. I’m not sure how you derived the average age of 40. However, determining the average age at the time of Nuh AS makes no difference on the message of Nuh AS.