The half-life of a specific radioactive compound is 20 years. The equation used to model this half-life is y = 5{\left( {\frac{1}{2}} \right)^{\frac{t}{{20}}}}, where t represents time. Currently, there is 5 pounds of this compound below the earth's surface. When will there only be 1 pounds of this compound left? Round your answer to the nearest year.

Question

The half-life of a specific radioactive compound is 20 years. The equation used to model this half-life is  y = 5{\left( {\frac{1}{2}} \right)^{\frac{t}{{20}}}}, where t represents time. Currently, there is 5 pounds of this compound below the earth's surface. When will there only be 1 pounds of this compound left? Round your answer to the nearest year.

anonymous · Answer

y=5(1/2)^t/20
where t = time when will there be one compound left?