SOLUTION: the max population that earth can sustain is 40 billion. if the current population is 4.2 billion, in how many years will the max population be reached? Assume that each year the p

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: the max population that earth can sustain is 40 billion. if the current population is 4.2 billion, in how many years will the max population be reached? Assume that each year the p      Log On


   

Question 751125: the max population that earth can sustain is 40 billion. if the current population is 4.2 billion, in how many years will the max population be reached? Assume that each year the population is 2% more than the previous year.
Found 2 solutions by nerdybill, timvanswearingen:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
the max population that earth can sustain is 40 billion. if the current population is 4.2 billion, in how many years will the max population be reached? Assume that each year the population is 2% more than the previous year.
.
Exponential growth equation:
A = Pe^(rt)
the problem give us:
P is 4.2
A is 40
r is .02
.
40 = 4.2e^(.02t)
40/4.2 = e^(.02t)
ln(40/4.2) = .02t
ln(40/4.2)/.02 = t
112.69 = t
or
113 years = t

Answer by timvanswearingen(106) About Me  (Show Source):
You can put this solution on YOUR website!
Start with 4,200,000,000 and multiply by 1.02. Continue to multiply each product by 1.02 until you reach 40,000,000,000 and you'll have your answer. The number of times you multiplied is the number of years it will take.