Each year, we use up half of what remains of some resource. To the nearest year, how many years will it take to use up 99.9% of what we know have of this resource?
Your question is super vague, but if we start from 100% on year 0, and eliminate half of our resources every year on, we will be at 0.0762939453% by the 17th year. The answer is 17, no nearest year rounding is needed.