if the half life of some radioactive isotope is 7,000 years and i start with 16 pounds of the isotope, how much is left after 21,000 years

Question

 I need the answer as well as the breakdown of how you got to it

Answer 1

A = a₀(0.5)^t/h

A = 16(0.5)^21000/7000

A = 16(0.5)³

A = 16(0.125)

A = 2

 

You have two pounds.