Please show me the step by step process to solve the following :

Question $4[30$ points$]$

The United Corporation company has the following purchases and sales during the year ended December $31,2019.$

Inventory and Purchases

Beginning: $200$ units @ $$84/$unit

February $17$: $200$ units @ $$78/$unit

July $29$: $100$ units @ $$72/$unit

Sales

March $17$: $100$ units

December $8$: $200$ units

The units have a selling price of $$95\mathrm{.}00$ per unit.

Specific Units Sold

March $17$: $60$ units from beginning inventory

$40$ units from the February $17$ purchase

December $8$: $100$ units from beginning inventory

$50$ units from the February $17$ purchase

$50$ units from the July $29$ purchase

a$)$ Given that United Corporation employs a perpetual inventory system, calculate the cost of goods available for sale and the number of units available for sale, as well as the units remaining in ending

inventory.

Cost of goods available for sale:

Units available for sale:

Units remaining in ending inventory:

b$)$ Please fill in the table by calculating the dollar value of cost of goods sold and ending inventory, as well as the gross profit earned by United Corporation using the following systems : FIFO, LIFO,

Weighted Average, and Specific Identification. Calculate weighted average cost per unit of merchandise inventory to the nearest cent.