Math homework please. How long would it take for the human population to disappear if we were decimated once a year?

The issue here is that decimation means 1 in every ten is taken away. What you have is nine of every ten. 

Umm yeah, I suck at math and reading today.  There would be >1 person left in 216 years and <1 person left in 217 years.

This post was edited by Livvie at October 19, 2019 12:36 PM MDT

Yea, we run into a problem figuring out how to decimate one person. 

Let’s assume they would die of loneliness, ...eventually. 

This post was edited by Don Barzini at October 19, 2019 12:36 PM MDT

Unfortunately, the word decimate has been corrupted and no longer exclusively refers to the 1 to 10 proportionality.

I am unimpressed because this corruption now increases the extension of the word decimate while decreasing its comprehension.

As has been said elsewhere, "Words should be used as precise instruments, not blunt objects."

Precision, I think, is a rare and perishable skill. This post was edited by Don Barzini at October 20, 2019 1:31 AM MDT

And possibly on its deathbed.

Not as long as idealistic oldsters like us are available to resuscitate it. Lol

Well, we are trying our best....

Precisely.

I agree. I meant it as 1/10 killed, as the Romans would do to soldiers for piss-poor performance in battle.

I learned its definition in high school in the early 60's---with no reference to the Romans.

Math:  1 decimeter = 1/10 of a meter. This post was edited by tom jackson at October 19, 2019 12:57 PM MDT

I just thought it an interesting historical tidbit.

historical
kill one in every ten of (a group of soldiers or others) as a punishment for the whole group.

It is,  but I didn't want it to be associated with that "time" in history as one of the links I read was trying to do in defending the meaning of "to destroy a very large number of them."

(You know, the old high school Latin saying:  "Latin is a language, as dead as it can be.  First it killed the Romans, and now it's killing me.")

One would have to be skilled in differential equations and the variable numbers could only be estimates.

Probably could just find the limit of a series.

I am an engineer by trade. Or was.

It is important to note the Q states decimated EVERY year. Which is to say, killing 10% of whatever the population is remaining from the previous year’s decimation. Essentially, 90% of the previous population would remain each year; with 7.7 B as a starting point, we reach 1 (and a decimal) person after 216 years, absent consideration for birthrate during that period- for which I tallied generously at 2-3 more years. 

This post was edited by Don Barzini at October 20, 2019 8:22 AM MDT

Askers pick. :)