Bachmann Products, Incorporated, has found that new products follow a learning curve. The first two units have been completed with the following results:

$\backslash$table$[[\backslash$table$[[$Units$],[$Produced$]],\backslash$table$[[$Marginal Labor$],[$Time$]]],[1,85\mathrm{.}00],[2,68\mathrm{.}00]]$

How much time will be needed to complete the $8^{th}$ unit?

$74\mathrm{.}00$ hours.

$54\mathrm{.}40$ hours.

$51\mathrm{.}00$ hours.

$43\mathrm{.}52$ hours.