Sabine owns and operates a part-time pet grooming business. She charges a flat rate of $40 to bathe and groom a dog. Last year, Sabine groomed 384 dogs. Her total costs were $4848, which included $3600 of fixed costs.

a. What are Sabine's variable costs per dog groomed?

b. Assuming her cost structure does not change, what would Sabine's total costs be in a year in which she groomed a total of 500 dogs?