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 $$26$ each.

$\backslash$table$[[$Purchases on December $7,10$ units @ $$12\mathrm{.}00$ cost$],[$Purchases on December $14,20$ units @$$18\mathrm{.}00$ cost$],[$Purchases on December $21,15$ units @$$20\mathrm{.}00$ cost$]]$

Required:

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