Exponential Functions problem ?

The remaining mass, M, in milligrams of a drug in a person's bloodstream after t hours is modeled by the relation M=500(1/2)1/2.

a) what's the initial mass of the drug?

b) what's the half life of the drug?

c) what's the mass of the drug in the bloodstream after 1 day?

Any help is much appreciated!!


Update: This is the relation as the teacher gave it to me. I don't have any more info

3 Answers

  • 2 months ago
    Favorite Answer

    I would assume that you relation should be:

    M(t) = 500(1/2)^t

    Initial mass is when t = 0

    i.e. M(0) = 500(1/2)⁰ => 500 mg

    Half-life occurs when t = 1 hour

    After 1 day, i.e. when t = 24 we have:

    M(24) = 500(1/2)²⁴ => 0.00003 mg

    or, 0.03 µg 


  • 2 months ago

    M=500(1/2)1/2. should actually read


    1/2 is half life

    t= time 1/2 an hour multiples

    that mean in 1/2 an hour, half of the drug is active(50%)

    initial mass is 500 mg

    after first (t=1)1/2 hr, 250 mg is remaining.

    after two(t=2), 1/2*1/2 =1/4 of 500 mg is remaining and so on

    in 24 hr 48 half hours are there


    now do the computation.

    did i make the problem clear to you?

  • 2 months ago

    You've mistyped the relation.  Where's the t?  Is some part of the expression an exponent?

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