Penny's Pencil Company had $69\mathrm{.}14$ thousand dollars in sales for the year $2020.$ Starting in $2021,$ Penny plans to invest $\backslash (9\mathrm{.}1\backslash \%\backslash )$ of their sales each year, and they expect sales to increase by $\backslash (6\backslash \%\backslash )$ each year over the next three years. Penny has access to an investment account earning an APR of $\backslash (1\mathrm{.}7\backslash \%\backslash )$ compounded continuously. Assume a continuous income stream.

a$.$ How much money will be in the investment account at the end of $2023?($Round your answer to three decimal places.$)$

thousand dollars

b$.$ How much money did Penny invest in the account between the start of $2021$ and the end of $2023?($Round your answer to three decimal places.$)$

thousand dollars

c$.$ How much interest did Penny earn on the investment between the start of $2021$ and the end of $2023?($Round your answer to three decimal places. Be sure to use unrounded intermediate values to determine the answer.$)$

thousand dollars