Can someone please help me with part b and c.

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- Jan 19th 2010, 07:32 AMTweetyexponential word problem
Can someone please help me with part b and c.

- Jan 19th 2010, 07:49 AMearboth
to a)

Plug in D = 10 and t = 5. Use a calculator. I've got $\displaystyle x \approx 5.353\ \rm{mg}$

to b)

Now D = 10 + 5.353 and t = 1. Use a calculator. I've got $\displaystyle x \approx 13.54897\ \rm{mg}$

to c)

Solve the equation for t:

$\displaystyle 3 = 15.353\cdot e^{-\frac18 t}~\implies~\dfrac{3}{15.353} = e^{-\frac18 t}$

Use logarithm:

$\displaystyle \ln\left(\dfrac{3}{15.353} \right) = -\frac18 t$

I'll leave the rest for you.

__Spoiler__: - Jan 19th 2010, 07:56 AMTweety
Thank you,

but D= the amount of dose given, so why have you added the answer to part 'a' , which is the amount of the drug in the bloodstream?

Cause I thought to put D = 20, - Jan 19th 2010, 08:04 AMearboth