document.write( "Question 1208600: Bismuth-210 is an isotope that radioactively decays by about 13% each day, meaning 13% of the remaining Bismuth-210 transforms into another atom (polonium-210 in this case) each day. If you begin with 215 mg of Bismuth-210, how much remains after 7 days?\r
\n" ); document.write( "\n" ); document.write( "After 7 days, mg of Bismouth-210 remains.
\n" ); document.write( "Round your answer to the nearest hundredth as needed.
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #846959 by ikleyn(52803) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "Bismuth-210 is an isotope that radioactively decays by about 13% each day, meaning 13% of the remaining Bismuth-210
\n" ); document.write( "transforms into another atom (polonium-210 in this case) each day. If you begin with 215 mg of Bismuth-210, how much remains after 7 days?
\n" ); document.write( "After 7 days, mg of Bismouth-210 remains.
\n" ); document.write( "Round your answer to the nearest hundredth as needed.
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "The remaining mass of the Bismuth-210 after 1 day is  215*(1-0.13) = 215*0.87 mg.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The remaining mass of the Bismuth-210 after 2 days is  215*0.87*0.87 = 215*0.87^2 mg.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The remaining mass of the Bismuth-210 after 3 days is  215*0.87^2*0.87 = 215*0.87^3 mg.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( ". . . . . and so on . . . . . \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The remaining mass of the Bismuth-210 after 7 days is  215*0.87^6*0.87 = 215*0.87^7  = 81.10978 mg  (rounded).    ANSWER\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "Solved, with explanations.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );