document.write( "Question 880717: The world population at the beginning of 1990 was 5.3 billion. Assume that the population continues to grow at 2% a year, find the function (Qt) that expresses
\n" ); document.write( "the world population in billions as a function of time t (in years) with t=0 corresponding with the beginning of 1990. If the population continues to grow at 2% a year, find the length of time required for the population to double \n" ); document.write( "

Algebra.Com's Answer #531665 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
The formula is:
\n" ); document.write( " $\"+Q%28t%29+=+5.3%28+1+%2B+.02+%29%5Et+\"$
\n" ); document.write( "where $\"+Q%28t%29+\"$ is in billions
\n" ); document.write( "------------------------------------
\n" ); document.write( "The population has doubled when
\n" ); document.write( " $\"+Q%28t%29+=+10.6+\"$ billion
\n" ); document.write( "I can then say:
\n" ); document.write( " $\"+10.6+=+5.3%28+1+%2B+.02+%29%5Et+\"$
\n" ); document.write( " $\"+2+=+1.02%5Et+\"$
\n" ); document.write( " $\"+log%282%29+=+t%2Alog%281.02%29+\"$
\n" ); document.write( " $\"+t+=+log%282%29+%2F+log%281.02%29+\"$
\n" ); document.write( " $\"+t+=+.30103+%2F+.0086+\"$
\n" ); document.write( " $\"+t+=+35.003+\"$
\n" ); document.write( "The population will double in 35 years
\n" ); document.write( "---------------
\n" ); document.write( "check:
\n" ); document.write( " $\"+Q%2835%29+=+5.3%28+1+%2B+.02+%29%5E35+\"$
\n" ); document.write( " $\"+Q%2835%29+=+5.3%2A1.02%5E35+\"$
\n" ); document.write( " $\"+Q%2835%29+=+5.3%2A2+\"$
\n" ); document.write( " $\"+Q%2835%29+=+10.6+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );