SOLUTION: given that the half life of a certain radioactive substance s 20 days and there are 5 grams present initially, the equation that models the situation is s(t)=5(1/2)^t/20. Find the

Question 546806: given that the half life of a certain radioactive substance s 20 days and there are 5 grams present initially, the equation that models the situation is s(t)=5(1/2)^t/20. Find the time when here will be 1 gram of the substance remaining
Answer by KMST(5328) (Show Source): You can put this solution on YOUR website!
So you have the equation ,
and want to find the time, , until you have .
That is a job for logarithms. Logarithm (base 10 is OK) of the left side is equal to logarithm of 1, which is zero. Let's work on the left side:

So, ---> --->
The approximate answer (according to my calculator) is t=46.44 days (46 days and 10.5 hours)
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