16 grams of radioactive material decays into 8 grams in 10 years. How long will it take to decay to 1 gram?
Choose the correct choice from the following.
A) 30 years	B) 42 years	C) 45 years	D) 40 years	E) 50 years
This radioactive material has half life after 10 years.   16 grams decays into 8 grams in 10 years.   Then 8 grams decays into 4 grams in next 10 years.   Then 4 grams decays into 2 grams in next 10 years.   Then 2 grams decays into 1 gram in next 10 years.   Thus 16 grams decays into 1 gram in 40 years.   ANSWER:40 years
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16 grams of radioactive material decays into 8 grams in 10 years. How long will it take to decay to 1 gram?