document.write( "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? \n" ); document.write( "

Algebra.Com's Answer #383457 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+n+\"$ = the number of 20 year periods
\n" ); document.write( "since 2000
\n" ); document.write( " $\"+100+=+6.1%2A2%5En+\"$ ( answer in billions )
\n" ); document.write( " $\"+2%5En+=+100%2F6.1+\"$
\n" ); document.write( " $\"+2%5En+=+16.3934+\"$
\n" ); document.write( " $\"+n%2Alog%282%29+=+log%28+16.3934%29+\"$
\n" ); document.write( " $\"+.30103n+=+1.21467+\"$
\n" ); document.write( " $\"+n+=+4.035+\"$
\n" ); document.write( " $\"+20n+=+20%2A4.035+\"$
\n" ); document.write( " $\"+20n+=+80.7+\"$
\n" ); document.write( "and $\"+2000+%2B+80+=+2080+\"$
\n" ); document.write( "In 2080 the world population will reach 100 billion
\n" ); document.write( "Here's the plot:
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-1%2C+6%2C+-10%2C+120%2C+6.1%2A2%5Ex+%29+\"$
\n" ); document.write( "The horizontal axis is number of 20 yr periods
\n" ); document.write( "The vertical axis is population in billions
\n" ); document.write( " \n" ); document.write( "

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