document.write( "Question 1199030: The half life of a certain isotope is 8.5 hours. If we have a sample of 20 ounces of that isotope, how much of it will remain after one full day?\r
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\n" ); document.write( "\n" ); document.write( "A) 0.28 ounces \r
\n" ); document.write( "\n" ); document.write( "B) 0.14 ounces \r
\n" ); document.write( "\n" ); document.write( "C) 1.41 ounces \r
\n" ); document.write( "\n" ); document.write( "D) 2.82 ounces \n" ); document.write( "

Algebra.Com's Answer #832728 by ikleyn(52802) $\"\"$ $\"About$

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document.write( "One full day is 24 hours.\r\n" );
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document.write( "24 hours is  how many half-lives ? - It is   = 2.82 half-lives, i.e. close to 3 half-lives.\r\n" );
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document.write( "Hence, after 24 hours, the remaining amount will be  about   =   of the initial amount, which is 20 ounces.\r\n" );
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document.write( "So, we can expect  something about  = 2.5 ounces for remaining mass.\r\n" );
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document.write( "The closest option is D).    ANSWER\r\n" );
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document.write( "All other optional masses are much lesser and much further in time than 3 half-lives; \r\n" );
document.write( "so, this MENTAL estimation is just enough to make a final conclusion.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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