How do I write the mathematical expression for this question?

"The value of a certain rare silver dollar was $60,000 in 1980. A price history of the silver dollar shows that it has been doubling in value every 30 years. Find an exponential growth model for A, the value of the coin (in dollars) t years after 1980. (Enter a mathematical expression.)

A =

Use your model to estimate the value (in dollars) of the coin in 2035. (Enter a number. Round to the nearest thousand dollars.)

$