The value of a certain rare silver dollar was $40,000 in 1980. A price history of the silver dollar shows that it has been doubling in value every 20 years. Find an exponential growth model for A, the value of the coin (in dollars) t years after 1980.(See Example 3 in this section.)A =

Use your model to estimate the value (in dollars) of the coin in 2015. Round to the nearest thousand dollars.$