Solve the missing values

Purchase	Q'ty	U Cost	Amount	End Inv	Amount	CGS
Jan	20	12	240	WAVG	?	?
Mar	15	15	225	FIFO	?	?
April	40	16	640	LIFO	?	?
Nov	50	20	1000
GAS	?	?	?	90
Retail Method				Gross Profit Method
	@ cost	@ price			@ cost	@ price
Cost ratio	[a] %			profit margin	25%
Begin Inv.	32,000.00	70,000.00		Begin Inv.	24,000.00
Purchase	135,000.00	280,000.00		Purchase	5,600.00
GAS	187,000.00	350,000.00		GAS	29,600.00
CGS / Sale	$ [b]	270,000.00		CGS / Sale	$ [e]	23,000.00
Ending Inv	$ [c]	$ [d]		Ending Inv	$ [f]

Solve the missing values ( question mark , a, b, c, d, e, f