A 70 kg patient needs to be staed on nitroglycerine (NTG) infusion. A 5 ml ampoule contains 5 mg/ml NTG. One ampoule is added to normal saline and to make a total of 500 ml solution. Calculate the rate of infusion if NTG is required at a rate of 10 mcg/min. (1 micro drip = 60 drops/ml )