I really need help with this, very long question. Every morning 20 grams of ointment has to be applied to a 65cm thigh & 40 cm calf. every 6 hours 20% of the 20 grams have to be reapplied. How many grams of ointment must be applied every 6 hours. And how long will a 120 gram tube of ointment last if the ointment is applied for 12 hours a day every day.