Cheque no, 1 was used to purchase a new executive office desk from Morgan Office Furniture for the owner less the trade in of his old desk. The new desk cost $2200 and he received cash back of $150 for the old desk. Both prices include GST. The old desk cost $500 and had a written down value of $90 at the time of sale. Record the trade ins, sales, purchase and Profit/loss on trade ins.