Question

A town's population is currently 500. If the population doubles every 70 years, what will the population be 280 years from now?

Answer 1

The population in 280 years will be 700

Answer 2

This question looks complicated but once you understand the process it should be easy!
So lets start by looking at in 280 years, how many times will it double?
well to find that answer we would divide 280 by 70. 
280/70=4.
Alright so in 280 years the population will double four times.
One way to solve this problem would be this way (for reference, doubled means we would multiply the number times two.):
500*2=1000
1000*2=2000
2000*2=4000
4000*2=8000
That is the population of 500 doubled 4 times. 
So the population would be 8,000 in 280 years