document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1005174>Question 1005174</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A bacteria colony grows continuously at an exponential rate. There are initially 1.6 million present. After 4 days, there are 6.6 million present. <BR>\n" );
document.write( "a. What is an equation modeling the number of bacteria present after \"d\" days? <BR>\n" );
document.write( "b. How many bacteria will be present after 9 days? <BR>\n" );
document.write( "c. How long will it take the number of bacteria to reach 90 million?\r<BR>\n" );
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document.write( "Can someone explain this in detail?  I am really having trouble with the question. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #621518 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=621518\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A bacteria colony grows continuously at an exponential rate. There are initially 1.6 million present. After 4 days, there are 6.6 million present.<BR>\n" );
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document.write( "y = ab^x<BR>\n" );
document.write( "a = 1.6 million<BR>\n" );
document.write( "6.6 million = 1.6*b^4<BR>\n" );
document.write( "b^4 = 4.125<BR>\n" );
document.write( "b = 1.425<BR>\n" );
document.write( "----<BR>\n" );
document.write( "a. What is an equation modeling the number of bacteria present after \"d\" days?<BR>\n" );
document.write( "y = 1.6*1.425^d<BR>\n" );
document.write( "----------------------- <BR>\n" );
document.write( "b. How many bacteria will be present after 9 days?<BR>\n" );
document.write( "y = 1.6*1.425^9 = 38.77 million<BR>\n" );
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document.write( "c. How long will it take the number of bacteria to reach 90 million?<BR>\n" );
document.write( "90 = 1.6*1.425^x<BR>\n" );
document.write( "1.425^x = 56.25<BR>\n" );
document.write( "x = log(56.25)/log(1.425)<BR>\n" );
document.write( "x = 11.38 days<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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document.write( "</TD></TR></TABLE>\n" );