Weighted average cost flow method under perpetual inventory system

The following units of a particular item were available for sale during the calendar year:

Jan. $1$

Inventory

$4,000$ units at $$50$

Apr. $19$

Sale

$2,500$ units

June $30$

Purchase

$4,500$ units at $$54$

Sept. $2$

Sale

$5,000$ units

Nov. $15$

Purchase

$2,000$ units at $$56$

Weighted Average cost Flow Method