37.
Moving Average is pretty much the average price paid for all units that the business has from 1st September to 27th:
(5 x $200) + (5 x $240) + (3 x $260) + (6 x $200) = $4180
To find the average price paid per unit, you divide the $4180 by the number of units purchased/owned over the month, which is 19.
$4180 / 19 = $220
To calculate average COGS, you just do $220 x 12 units sold over the month (7 on Sep. 7 and 5 on Sep. 27) to get $2640
39.
LIFO just means that the last good purchased is assumed to be the first one sold. As it is PERPETUAL, accounts are recorded AS TRANSACTIONS OCCUR, so the calculation of the last good purchased may change depending on when goods are purchased and sold. Keeping this in mind, September 7th shows 7 units being sold. At this time, the only goods that are owned/purchased are the (5 x $200) from Sep. 1 and the (5 x $240) from Sep. 5. Thus, the cost of the last 7 units are (5 x $240) + (2 x $200) = $1600. On Sep. 27, another 5 units are sold. At that time, the company has the remaining (3 x $200) from Sep. 1, (3 x $260) from Sep. 12, and (6 x $200) from Sep. 25. The cost of the most recently purchased units are (5 x $200) = $1000.
$1600 (From Sep. 7 COGS) + $1000 (From Sep. 27 COGS) = $2600
40.
Similar to last time, but accounts are accrued PERIODICALLY. As it is Periodic, it is done at the end of the accounting period (which is the month of September in this case). For this, LIFO uses the most recently purchased good in the account (which is Sep. 25 followed by Sep. 12 etc.) in calculating COGS. For this, we can see that 12 units were sold over the month. In calculating LIFO:
(6 x $200) [These 6 units are from Sep. 25] + (3 x $260) [These 3 units are from Sep. 12] + (3 x $240) [These 3 remaining units are from Sep. 3 and make up the total 12 units sold]. So, (6 x $200) + (3 x $260) + (3 x $240) = $2700.
Based on this, you still have 7 unsold units that will end up as ending inventory: (2 x $240) from Sep. 3 that haven't been accounted for, as well as the initial (5 x $200) from Sep. 1. Thus, (2 x $240) + (5 x $200) = $1480
I hope this helps. If not, feel free to send me a message, and i can try to clarify a bit further