How much more money should be invested now in order to receive $$1,250\mathrm{.}00$ at the beginning of each month for $10$ months instead of $$260\mathrm{.}00$ at the beginning of each month for $30$ months? Assume an interest rate of $5\mathrm{.}00\%$ compounded annually.

How much should Robert's dad invest in a savings account today, to be able to pay for Robert's rent for the next five years, if the rent is $$450,$ payable at the beginning of each month? The savings account earns $3\mathrm{.}26\%$ compounded monthly.