Dinosaur fossils | Science homework help

Dinosaur fossils are often dated by using an element other than carbon, like potassium-40, that has a longer half life (in this case, approximately 1.25 billion years). Suppose the minimum detectable amount is 0.1% and a dinosaur is dated with 40K to be 69 million years old. Is this possible? What is the maximum age of a fossil that we could date using 40K? (Round your answer to one decimal place.)