$4-94.$ A college loan plan now offers student loans at

$4\%$ annual interest. After two years the interest rate will

increase to $6\%$ per year. If you borrow $$5,000$ now and

$$5,000$ each year thereafter for a total of four installments

of $$5,000$ each, how much will you owe at the end of

the fourth year? Interest is computed at the end of each

year. $(4\mathrm{.}13)$