A radioactive element decays at a rate of 5% annually. There are 40 grams of the substance present. How much of the substance

Question

A radioactive element decays at a rate of 5% annually. There are 40 grams of the substance present.
How much of the substance remains after 30 years (to the nearest tenth)?
When will the amount of the substance drop to below 20 grams (to the nearest year)?

Kunduz · Accepted Answer

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