The ratio of total cholesterol to HDL cholesterol can be found by dividing the total cholesterol by the HDL cholesterol. So, the patient's ratio of total cholesterol to HDL cholesterol is:185 mg/dl ÷ 40 mg/dl = 4.625 mg/dl (dividing both numerator and denominator by 5)⇒ 37/8 (after simplification).
Thus, the patient's ratio of total cholesterol to HDL cholesterol is 37/8