document.write( "Question 159165This question is from textbook Elementary and Intermediate Algebra: A Combined Approach
\n" ); document.write( ": Suppose that a certain radioactive substance has a half-life of 20 years. If there are presently 2500 milligrams of the substance, how much, to the nearest milligram, will remain after 50 years? \n" ); document.write( "
Algebra.Com's Answer #117294 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
Suppose that a certain radioactive substance has a half-life of 20 years. If there are presently 2500 milligrams of the substance, how much, to the nearest milligram, will remain after 50 years?
\n" ); document.write( ":
\n" ); document.write( "Using the half-life formula: A = Ao*(2^(-t/h))
\n" ); document.write( "Where:
\n" ); document.write( "A = final amt
\n" ); document.write( "Ao = initial amt (2500 mg)
\n" ); document.write( "t = time (50 yrs)
\n" ); document.write( "h = half-life of the substance (20 yrs)
\n" ); document.write( ":
\n" ); document.write( "A = 2500 * 2^(-50/20)
\n" ); document.write( ":
\n" ); document.write( "A = 2500 * 2^(-5/2)
\n" ); document.write( ":
\n" ); document.write( "Use a calculator to find 2^(-5/2) value
\n" ); document.write( "A = 2500 * .1767767
\n" ); document.write( ":
\n" ); document.write( "A = 441.94 ~ 442 mg \n" ); document.write( "
\n" );