document.write( "Question 1189594: The mass of a substance, which follows a continuous exponential growth model, is being studied in a lab. The doubling time for this substance was observed to be 23 days. There were 72.6 mg of the substance present at the beginning of the study.\r
\n" ); document.write( "\n" ); document.write( "(a) Let t be the time (in days) since the beginning of the study, and let
\n" ); document.write( "y be the amount of the substance at time t. Write a formula relating y to t. Use exact expressions to fill in the missing parts of the formula. Do not use approximations.\r
\n" ); document.write( "\n" ); document.write( "(b) How much will be present in 8 days?
\n" ); document.write( "Do not round any intermediate computations, and round your
\n" ); document.write( "answer to the nearest tenth. \n" ); document.write( "
Algebra.Com's Answer #821021 by ikleyn(52802)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "The mass of a substance, which follows a continuous exponential growth model, is being studied in a lab.
\n" ); document.write( "The doubling time for this substance was observed to be 23 days.
\n" ); document.write( "There were 72.6 mg of the substance present at the beginning of the study.
\n" ); document.write( "(a) Let t be the time (in days) since the beginning of the study, and let
\n" ); document.write( "y be the amount of the substance at time t. Write a formula relating y to t.
\n" ); document.write( "Use exact expressions to fill in the missing parts of the formula. Do not use approximations.
\n" ); document.write( "(b) How much will be present in 8 days?
\n" ); document.write( "Do not round any intermediate computations, and round your
\n" ); document.write( "answer to the nearest tenth.
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\n" ); document.write( "\n" ); document.write( "            This problem can be solved in couple of lines with very short simple calculations.\r
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\n" ); document.write( "\n" ); document.write( "            See my solution below.\r
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document.write( "As the mass is doubling every 23 days, we can write\r\n" );
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document.write( "    y = 72.6*2^(t/23),      (1)\r\n" );
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document.write( "where t is the time in days.  It is LITERAL TRANSLATION of what the problem states.\r\n" );
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document.write( "Formula (1) is the answer to question (a).\r\n" );
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document.write( "To answer question (b), simply substitute t= 8 days into the formula and calculate \r\n" );
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document.write( "    y = 72.6*2^(8/23) = use your calculator = 92.39377 milligrams (rounded).\r\n" );
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\n" ); document.write( "\n" ); document.write( "That is all.   The problem is just solved in full.\r
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\n" ); document.write( "\n" ); document.write( "It is easy and a   S T A N D A R D   way to solve exponential growth problems,
\n" ); document.write( "when the doubling period is given as an input data.\r
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\n" ); document.write( "\n" ); document.write( "May god save you from making tons unnecessary and nonsensical calculations,  which @Theo does in his post.\r
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\n" ); document.write( "\n" ); document.write( "For peace in your mind,  simply ignore his post.  It is definitely wrong way to teach.\r
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\n" ); document.write( "\n" ); document.write( "To see many similar and different solved problems of this kind,  look into the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Population growth problems \r
\n" ); document.write( "\n" ); document.write( "    - Radioactive decay problems \r
\n" ); document.write( "\n" ); document.write( "    - Carbon dating problems \r
\n" ); document.write( "\n" ); document.write( "    - Bacteria growth problems \r
\n" ); document.write( "\n" ); document.write( "    - A medication decay in a human's body \r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \"Logarithms\".\r
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\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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