Required information

$[$The following information applies to the questions displayed below.$]$

Trey Monson starts a merchandising business on December $1$ and enters into the following three inventory purchases. Monson uses a perpetual inventory system. Also, on December $15,$ Monson sells $15$ units for $$34$ each.

Purchases on December $7$

Purchases on December $14$

Purchases on December $21$

$10$ units@$$20\mathrm{.}00$ cost

units@$$26\mathrm{.}00$ cost

units@$$28\mathrm{.}00$ cost

Required: Determine the costs assigned to the December $31$ ending inventory based on the FIFO method.