A 56-year-old man was admitted to the hospital with a myocardial infarction.At admission,his serum creatinine level was 1.2 mg/dL,and his creatinine clearance rate was 100 mL/minute.Over the next 3 days,he had several periods of hypotension,and his serum creatinine level increased to 3.6 mg/dL.Assuming that he is in steady-state balance for creatinine level (i.e.,amount excreted = amounted produced),what is his predicted creatinine clearance rate?