The balance A (in dollars) in a savings account is given by A = 7000e.05t, where t is measured in years. Find the rate at which the balance is changing when t = 1 year, t = 10 years, and t = 50 years. (Round your answers to two decimal places.) (a) t = 1 year $4 per year (b) t = 10 years per year (c) t = 50 years per year