More accounting questions... PLEASE HELP!!!!?

Question

Mar 1 - Beginning Inventory --- 20 units @ $76

Mar 7 - Purchase --- 70 units @ $80

Mar 18 - Sale --- 25 units

Mar 22 - Purcahse --- 10 units @ $88

Mar 29 - Sale --- 40 units

Under Perpetual System using Average-Cost Method - what is the Cost of Goods Sold

Using Specific Identification Method - what is the ending inventory?

What is the gross margin from sales for the following accounts and balances??

Advertising Expense - 14000

Common Stock - 100000

Dividends - 21000

Freight-In - 7000

Freight Out Expense - 10000

Interest Income - 24000

Merchandise Inventory (Jan 1) - 70000

Merchandise Inventory (Dec 31) - 56000

Purcahses - 60000

Purcahses Returns and Allowans - 4000

Rent Expense - 9000

Retained Earnings - 40000

Sales - 152000

Sales Returns and Allowances - 19000

Wages Expense - 32000

Answer 1

Mar 1 - Beginning Inventory --- 20 units @ $76

Mar 7 - Purchase --- 70 units @ $80

(Ave cost: $7120/90 = $79.11)

Mar 18 - Sale --- 25 units

(COGS: 25 x $79.11 = $1977.75)

Mar 22 - Purcahse --- 10 units @ $88

(Ave cost: $6022.15/75 = $80.30

Mar 29 - Sale --- 40 units

(COGS: 40 x $80.30 = $3212)

Total COGS = $1977.75 + $3212 = $5189.75

Using Specific Identification Method - what is the ending inventory?

This question cannot be answered cos you've left out critical info on which sale came from which purchase.

What is the gross margin from sales for the following accounts and balances??

Sales - 152000

Sales Returns and Allowances - (19000)

Net sales $133000

less:

COGS-

Merchandise Inventory (Jan 1) - 70000

Purcahses - 60000

Purcahses Returns and Allowans - (4000)

Freight-In - 7000

Merchandise Inventory (Dec 31) - (56000)

COGS $77000

Gross margin = sales - COGS

= 56000