Marsden Computing buys end-of-range computers and sells them to the general public at monthly auctions. Its transactions for the past three months have been as follows (on 1 January it held 20 computers which had cost £550 each):

January: Bought 300 computers at £550 each and sold 260 for £700 each February  Bought 240 computers at £650 each and sold 280 for £700 each

March: Bought 300 computers at £600 each and sold 290 for £680 each.

Prepare the trading account for the three-month period, assuming

(a) a FIFO inventory valuation method

(b) an AVCO inventory valuation method.