Bob operates a plumbing business and this year the 3-year old van he used in the business was destroyed in a traffic accident. The van was originally purchased for $20,000 and the adjusted basis was $5, 800 at the time of the accident. Although the van was worth $6,000 at the time of accident, insurance only paid Bob $1, 200 for the loss. What is the amount of Bob's casualty loss deduction?