MRCS-0967

A 77-year-old woman’s renal function is tested. The following results were obtained during a 24-h period: Urine flow rate: 2. 0 ml/min, Urine inulin: 0.5 mg/ml, Plasma inulin: 0.02 mg/ml, Urine urea: 220 mmol/l, Plasma urea: 5 mmol/l. What is the urea clearance?