SOLUTION: Hi, can you show me how to solve the following word problem using linear equations? In 2009, the population was 6.8 billion. It is estimated that the annual growth rate is 0.07 b

Algebra ->  Equations -> SOLUTION: Hi, can you show me how to solve the following word problem using linear equations? In 2009, the population was 6.8 billion. It is estimated that the annual growth rate is 0.07 b      Log On


   



Question 757175: Hi, can you show me how to solve the following word problem using linear equations? In 2009, the population was 6.8 billion. It is estimated that the annual growth rate is 0.07 billion. Assuming that the growth rate stays the same, in what year will the population reach 8.5 billion?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
The sense best found is that this is arithmetic progression.
YEAR_______0 is year 2009__________POPULATION(Billions)
2009_______0__________6.8
2010_______1__________6.8%2B0.07
2011_______2__________6.8%2B0.07%2B0.07
(???)______n__________6.8%2B0.07n

What is n when the population is 8.5 billion? Then the year is 2009%2Bn.

6.8%2B%280.07%29n=8.5
Find n.