Corey invested $$2,200$ 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 $4\mathrm{.}70\%$ 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 at the end of the first $7$ years.

$$64,503\mathrm{.}49$

$$65,004\mathrm{.}97$

$$35,976\mathrm{.}91$

$$36,822\mathrm{.}37$

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

$$64,503\mathrm{.}49$

$$65,004\mathrm{.}97$

$$56,611\mathrm{.}50$

$$36,822\mathrm{.}37$

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

$$16,604\mathrm{.}97$

$$16,103\mathrm{.}49$

$$14,415\mathrm{.}84$

$$2,189\mathrm{.}13$