Application of logs












-2












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The number of milligrams, $d$, of a drug remaining in a patient's bloodstream, $t$ hours after it has been administered, is given by the equation $d = 5(2.7^{.04t})$. To the nearest minute, how long will it take until only $2.5$ mg of the drug remains in the system?



First, I set the equation equal to 2.5 and solved for $t$, where $t=1.7$. However, I am way off from my teacher's answer which was 31 hours and 45 minutes. I'm uncertain of another way to solve the problem. What else do I need to do?










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  • 3




    $begingroup$
    I think the tag algebraic-topology should be removed
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:23










  • $begingroup$
    Use MathJax for typesetting. It is not possible to read the equation describing the evolution of $d(t)$ as currently posted.
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:24






  • 1




    $begingroup$
    The equation that you gave grows over time, are you sure that you have posted it correctly?
    $endgroup$
    – Gnumbertester
    Jan 24 at 3:29
















-2












$begingroup$


The number of milligrams, $d$, of a drug remaining in a patient's bloodstream, $t$ hours after it has been administered, is given by the equation $d = 5(2.7^{.04t})$. To the nearest minute, how long will it take until only $2.5$ mg of the drug remains in the system?



First, I set the equation equal to 2.5 and solved for $t$, where $t=1.7$. However, I am way off from my teacher's answer which was 31 hours and 45 minutes. I'm uncertain of another way to solve the problem. What else do I need to do?










share|cite|improve this question











$endgroup$








  • 3




    $begingroup$
    I think the tag algebraic-topology should be removed
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:23










  • $begingroup$
    Use MathJax for typesetting. It is not possible to read the equation describing the evolution of $d(t)$ as currently posted.
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:24






  • 1




    $begingroup$
    The equation that you gave grows over time, are you sure that you have posted it correctly?
    $endgroup$
    – Gnumbertester
    Jan 24 at 3:29














-2












-2








-2





$begingroup$


The number of milligrams, $d$, of a drug remaining in a patient's bloodstream, $t$ hours after it has been administered, is given by the equation $d = 5(2.7^{.04t})$. To the nearest minute, how long will it take until only $2.5$ mg of the drug remains in the system?



First, I set the equation equal to 2.5 and solved for $t$, where $t=1.7$. However, I am way off from my teacher's answer which was 31 hours and 45 minutes. I'm uncertain of another way to solve the problem. What else do I need to do?










share|cite|improve this question











$endgroup$




The number of milligrams, $d$, of a drug remaining in a patient's bloodstream, $t$ hours after it has been administered, is given by the equation $d = 5(2.7^{.04t})$. To the nearest minute, how long will it take until only $2.5$ mg of the drug remains in the system?



First, I set the equation equal to 2.5 and solved for $t$, where $t=1.7$. However, I am way off from my teacher's answer which was 31 hours and 45 minutes. I'm uncertain of another way to solve the problem. What else do I need to do?







logarithms applications






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edited Jan 24 at 3:49









Gnumbertester

670114




670114










asked Jan 24 at 3:17









BibliophileBibliophile

818




818








  • 3




    $begingroup$
    I think the tag algebraic-topology should be removed
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:23










  • $begingroup$
    Use MathJax for typesetting. It is not possible to read the equation describing the evolution of $d(t)$ as currently posted.
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:24






  • 1




    $begingroup$
    The equation that you gave grows over time, are you sure that you have posted it correctly?
    $endgroup$
    – Gnumbertester
    Jan 24 at 3:29














  • 3




    $begingroup$
    I think the tag algebraic-topology should be removed
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:23










  • $begingroup$
    Use MathJax for typesetting. It is not possible to read the equation describing the evolution of $d(t)$ as currently posted.
    $endgroup$
    – Aditya Dua
    Jan 24 at 3:24






  • 1




    $begingroup$
    The equation that you gave grows over time, are you sure that you have posted it correctly?
    $endgroup$
    – Gnumbertester
    Jan 24 at 3:29








3




3




$begingroup$
I think the tag algebraic-topology should be removed
$endgroup$
– Aditya Dua
Jan 24 at 3:23




$begingroup$
I think the tag algebraic-topology should be removed
$endgroup$
– Aditya Dua
Jan 24 at 3:23












$begingroup$
Use MathJax for typesetting. It is not possible to read the equation describing the evolution of $d(t)$ as currently posted.
$endgroup$
– Aditya Dua
Jan 24 at 3:24




$begingroup$
Use MathJax for typesetting. It is not possible to read the equation describing the evolution of $d(t)$ as currently posted.
$endgroup$
– Aditya Dua
Jan 24 at 3:24




1




1




$begingroup$
The equation that you gave grows over time, are you sure that you have posted it correctly?
$endgroup$
– Gnumbertester
Jan 24 at 3:29




$begingroup$
The equation that you gave grows over time, are you sure that you have posted it correctly?
$endgroup$
– Gnumbertester
Jan 24 at 3:29










1 Answer
1






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-2












$begingroup$

d = 5*(2.7^.04t) //(original equation)
2.5 = 5*(2.7^.04t) //(set equation equal to 2.5)
0.5 = 2.7^.04t //(divide by 5 on both sides)
log base 2.7 of 0.5 = 0.04t //(log function)
t = 17.446241... //(Answer)



You should probably talk to your teacher and ask her how he/she did the question.






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    -2












    $begingroup$

    d = 5*(2.7^.04t) //(original equation)
    2.5 = 5*(2.7^.04t) //(set equation equal to 2.5)
    0.5 = 2.7^.04t //(divide by 5 on both sides)
    log base 2.7 of 0.5 = 0.04t //(log function)
    t = 17.446241... //(Answer)



    You should probably talk to your teacher and ask her how he/she did the question.






    share|cite|improve this answer









    $endgroup$


















      -2












      $begingroup$

      d = 5*(2.7^.04t) //(original equation)
      2.5 = 5*(2.7^.04t) //(set equation equal to 2.5)
      0.5 = 2.7^.04t //(divide by 5 on both sides)
      log base 2.7 of 0.5 = 0.04t //(log function)
      t = 17.446241... //(Answer)



      You should probably talk to your teacher and ask her how he/she did the question.






      share|cite|improve this answer









      $endgroup$
















        -2












        -2








        -2





        $begingroup$

        d = 5*(2.7^.04t) //(original equation)
        2.5 = 5*(2.7^.04t) //(set equation equal to 2.5)
        0.5 = 2.7^.04t //(divide by 5 on both sides)
        log base 2.7 of 0.5 = 0.04t //(log function)
        t = 17.446241... //(Answer)



        You should probably talk to your teacher and ask her how he/she did the question.






        share|cite|improve this answer









        $endgroup$



        d = 5*(2.7^.04t) //(original equation)
        2.5 = 5*(2.7^.04t) //(set equation equal to 2.5)
        0.5 = 2.7^.04t //(divide by 5 on both sides)
        log base 2.7 of 0.5 = 0.04t //(log function)
        t = 17.446241... //(Answer)



        You should probably talk to your teacher and ask her how he/she did the question.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 28 at 4:04









        DhanushDhanush

        212




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