You need to prepare 50g of an ointment with 15% of zinc oxide. However, your pharmacy has no zinc oxide powder and the only thing you have is two lots of zinc oxide ointment containing, respectively, 50% and 5% of zinc oxide.

1. How many grams of the 50% ointment you need to prepare this formula?

15g ointment at 50%

Step-by-step explanation:

Data

We need to prepare 50g of an ointment with 15% of zinc oxide (O15)

with a Lote 1 = 50% zinc oxide

50% ⇒ 100g oinment 50g are zinc oxide, so

50g ointment 15% ⇒ 50g oinment*15zo/100g ointment = 7.5g zo, also

g ointment = 100g ointment*7.5g zo*/50g zo = 15g ointment