Brian invested $$1,900$ at the beginning of every $6$ months in an RRSP for $11$ years. For the first $7$ years it earned interest at a rate of $4\mathrm{.}50\%$ compounded semi$-$annually and for the next $4$ years it earned interest at a rate of $5\mathrm{.}20\%$ compounded semi$-$annually.

a$.$ Calculate the accumulated value of his investment after the first $7$ years.

$$0\mathrm{.}00$

Round to the nearest cent

b$.$ Calculate the accumulated value of his investment at the end of $11$ years.

$$0\mathrm{.}00$

Round to the nearest cent

c$.$ Calculate the amount of interest earned from the investment.

$$0\mathrm{.}00$

Round to the nearest cent