The expression for the balance (b) in terms of the number of years (t) can be written as
... b = 2000·2^(t/19) . . . . . . the amount grows exponentially, and is is doubled when t=19
Then for t=5, the balance is
... b = 2000·2^(5/19) ≈ 2400
The best choice is ...
... A. $2400
