SOLUTION: A radioactive substance has a halflife of 120 years. If 200mg of substance was present, how much of the substance remains after 340 years?

Question 841973: A radioactive substance has a halflife of 120 years. If 200mg of substance was present, how much of the substance remains after 340 years?
Answer by josgarithmetic(39623) (Show Source): You can put this solution on YOUR website!
Decay Equation in general, .
A = amount after time t
I = initial amount when t=0
k = a constant
At half-life, and you would want to find k for a given or known t.

You are given that t=120 for the half life and so you can calculate and find the value for k.
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