$27.$ Mrs White contributed $$2000$ to an RRSP account at the beginning of each

half of year for the past $15$ years. The plan earned $5\mathrm{.}8\%$ compounded annually

for the first $10$ years and $6\%$ compounded semi$-$annually for the last $5$ years.

She decided to convert her RRSP to a Registered Retirement Income Fund

$($RRIF$)$ and intend to withdraw equal amounts at the beginning of each month for

$20$ years. What monthly amount can be withdrawn by Mrs White if the RRIF

earns $5\mathrm{.}5\%$ compounded monthly?