Find the interest rate $($or rates of return$)$ in each of the following situations. Do not round intermediate calculations. Round your answers to the nearest whole number.

You borrow $$660$ and promise to pay back $$726$ at the end of $1$ year.

$\%$

You lend $$660$ and receive a promise to be paid $$726$ at the end of $1$ year.

$\%$

You borrow $$80,000$ and promise to pay back $$296,578$ at the end of $10$ years.

$\%$

You borrow $$9,000$ and promise to make payments of $$2,684\mathrm{.}80$ at the end of each of the next $5$ years.

$\%$