SOLUTION: I really need help with this one. I am trying to plug in numbers and i am not getting it. The amount of a radioactive tracer remaining ater t days is given by A=Aoe^-0.18t, where

Question 79522: I really need help with this one. I am trying to plug in numbers and i am not getting it.
The amount of a radioactive tracer remaining ater t days is given by A=Aoe^-0.18t, where Ao is the starting amount at the beginning of the time period. How much should be acquired now to have 40 grams remaining after 3 days?
a. 47.9 gm
b. 48.8 gm
c. 61.6 gm
d. 68.6 gm

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The amount of a radioactive tracer remaining ater t days is given by A=Aoe^-0.18t, where Ao is the starting amount at the beginning of the time period. How much should be acquired now to have 40 grams remaining after 3 days?
------------
40 = Aoe^(-0.18*3)
40 = Ao e^(-0.54)
Ao = 40/e^(-0.54)
Ao = 40/0.582748...
Ao = 68.64 grams (this needs to be the beginning amount)
===========
cheers,
Stan H.
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