This is for all my math geeks out there.

OK so since I can't google this let me not

700 million?

Like 8.5 hours I think?

4^(4*x) = 5,600,000,000

solve for x and then...

Years = (x*30)/(365*24*60)

I think it's worded wrong.

"those 4 people tell another 4 people"...I think it means that each one tells 4 people.

About 10.5 hours, I think. Because it is an exponential occurrence.

4^x = 5.6 billion (x = number of half hours it takes to tell the whole world)

ln(4^x) = ln(5.6 billion)

x = ln(5.6 billion)/ln(4)

x = 21.059

x/2 = 10.53 hours

I could be wrong though. I haven't done straight logarithms like this for at least three years.

Impossible, more people than 4 are born and die per 30 minutes

Y'all are awful at math I'm not going to actually solve it but it's not that complex.

This is math/physics, when you are given a condition, that's it. "You have to deal."

This. I just changed it.

Lemme not

Also this

It won't take that long. It's a problem involving exponentials, but I'm too lazy to do the math.

8 hours?? I don't feel like getting too into this

4^16 is a bit over 4 billion and 4^17 is over 17 billion tho, so 17 must be x (assuming they wait exactly 30 minutes, in which case you need a whole number) and x/2 is 8.5.

Don't use logs on this sort of thing, just makes it harder; just do 4*4*4 etc. till you get where you want.

First 30 minutes: 4
1 hour: 16
1.5 hours: 64
2 hours: 256
2.5 hours: 1,024
3 hours: 4,096
3.5 hours: 16,384
4 hours: 65,536
4.5 hours: 262,144
5 hours: 1,048,576
5.5 hours: 4,194,304
6 hours: 16,777,216
6.5 hours: 67,108,864
7 hours: 268,435,456
7.5 hours: 1,073,741,824
8 hours: 4,294,967,296

It's a little over 8 hours, but way less than 8.5 hours. I can probably get a little more detailed if you want the exact answer...

your so smart