Answer:

Step-by-step explanation:
The exponential decrease formula that we must use is:

Where A is the amount of thorium as a function of time
is the initial amount and k is the decrease rate
We know that initially there are 50 gr and that you decay 50% every 1.9 years.
So


We solve the equation for k





After 22.8 years the amount of thorium that exists is:


Answer:
i think its b
Step-by-step explanation:
Step-by-step explanation:
my answer is definitely i mean in statistics in math problem
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