Final answer:
To prepare 1 pound of a 0.2% hydrocortisone ointment, 907 mg of hydrocortisone are needed. This is determined by converting the pound to grams and then calculating the amount of hydrocortisone based on the percentage strength of the ointment.
Step-by-step explanation:
The question is asking how many milligrams (mg) of hydrocortisone are necessary to prepare a 0.2% hydrocortisone ointment that weighs one pound. To find the answer, we first convert one pound to grams, knowing that one pound is equivalent to 453.592 grams. A 0.2% ointment means that there are 0.2 grams of hydrocortisone in every 100 grams of ointment. Therefore, we set up a proportion to find out how many grams are in 453.592 grams, which is the total weight of the ointment.
0.2 grams / 100 grams = x grams / 453.592 grams
By cross-multiplying and solving for x, we find that:
x = (0.2 * 453.592) / 100
x = 0.907184 grams, or 907.184 mg
Therefore, the correct answer is (A) 907 mg to prepare 1 pound of 0.2% hydrocortisone ointment.