Question 55177
The amount of a radioactive tracer remaining after t days is given by {{{highlight(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=40
t=3
We're solving for Ao.
{{{40=Aoe^(-.18*3)}}}
{{{40=Aoe^(-.54)}}}
{{{40=Ao*.5827482524}}}  Scientific Calculator required for that.
{{{40/.5827482524=Ao*.5827482524/.5827482524}}}
{{{68.64027449=Ao}}}
Round off to whatever your teacher asks for.
Happy Calculating!!!