document.write( "Question 631377: A hospital purchased 40 grams of a substance.Eight days later,when a doctor wanted to use some of the substance,he found that only 20 grams remained.Predict the amount remaining two weeks after the purchase of the substance.(Please show the solution.) \n" ); document.write( "

Algebra.Com's Answer #397524 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
This assumes that the substance is
\n" ); document.write( "decreasing at a linear rate ( straight line ).
\n" ); document.write( "The rate of decrease is
\n" ); document.write( " $\"+-20+%2F+8+=+-20%2F8+\"$
\n" ); document.write( " $\"+-20%2F8+=+-5%2F2+\"$ grams/day
\n" ); document.write( "----------------
\n" ); document.write( "Let grams of substance remaining = $\"+S+\"$
\n" ); document.write( "Let $\"+d+\"$ = days since the purchase
\n" ); document.write( " $\"+S+=+-%285%2F2%29%2Ad+%2B+b+\"$
\n" ); document.write( " $\"+b+\"$ is the grams present when $\"+d+=+0+\"$ , so
\n" ); document.write( " $\"+b+=+40+\"$
\n" ); document.write( " $\"+S+=+-%285%2F2%29%2Ad+%2B+40+\"$
\n" ); document.write( "Two weeks after purchase is 14 days
\n" ); document.write( " $\"+S+=+-%285%2F2%29%2A14+%2B+40+\"$
\n" ); document.write( " $\"+S+=+-35+%2B+40+\"$
\n" ); document.write( " $\"+S+=+5+\"$
\n" ); document.write( "There are 5 grams remaining after 2 weeks
\n" ); document.write( "Here's the plot:
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-2%2C+20%2C+-2%2C+50%2C+-%285%2F2%29%2Ax+%2B+40+%29+\"$ \n" ); document.write( "

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