SOLUTION: in the year 2000 the population of yhe world was 6.1 billion. The doubling time of the world population is 20 years. In which year will the world population reach 100 billion if it

Algebra ->  Triangles -> SOLUTION: in the year 2000 the population of yhe world was 6.1 billion. The doubling time of the world population is 20 years. In which year will the world population reach 100 billion if it      Log On


   

Question 608972: in the year 2000 the population of yhe world was 6.1 billion. The doubling time of the world population is 20 years. In which year will the world population reach 100 billion if it continues to grow at the same rate?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +n+ = the number of 20 year periods
since 2000
+100+=+6.1%2A2%5En+ ( answer in billions )
+2%5En+=+100%2F6.1+
+2%5En+=+16.3934+
+n%2Alog%282%29+=+log%28+16.3934%29+
+.30103n+=+1.21467+
+n+=+4.035+
+20n+=+20%2A4.035+
+20n+=+80.7+
and +2000+%2B+80+=+2080+
In 2080 the world population will reach 100 billion
Here's the plot:
+graph%28+400%2C+400%2C+-1%2C+6%2C+-10%2C+120%2C+6.1%2A2%5Ex+%29+
The horizontal axis is number of 20 yr periods
The vertical axis is population in billions