Use the fact that the quantity of a radioactive substance after t years is given by where is the original amount of radioactive material and k is its half-life (the number of years it takes for half the radioactive substance to decay). The half-life of strontium-90 is 25 years. Find the amount of strontium-90 remaining after 9 years if Round your answer to one decimal place.
A) 13.6 kg
B) 72.5 kg
C) 7.5 kg
D) 119.4 kg
E) 0.2 kg

Question

Use the fact that the quantity of a radioactive substance after t years is given by where is the original amount of radioactive material and k is its half-life (the number of years it takes for half the radioactive substance to decay).   The half-life of strontium-90 is 25 years. Find the amount of strontium-90 remaining after 9 years if Round your answer to one decimal place. 
A) 13.6 kg 
B) 72.5 kg 
C) 7.5 kg 
D) 119.4 kg 
E) 0.2 kg

Quizplus · Accepted Answer

The Answer of Use the fact that the quantity of a radioactive substance after t years is given by where is the original amount of radioactive material and k is its half-life (the number of years it takes for half the radioactive substance to decay).   The half-life of strontium-90 is 25 years. Find the amount of strontium-90 remaining after 9 years if Round your answer to one decimal place. 
A) 13.6 kg 
B) 72.5 kg 
C) 7.5 kg 
D) 119.4 kg 
E) 0.2 kg

Use the Fact That the Quantity of a Radioactive Substance