Prepare 180 g of Lotrimin 0.05% cream. In stock, you have 200 g each of Lotrimin 0.025% cream and Lotrimin 0.1% cream.

Question

How much is needed of each?

Answer 1

Let x = amount of the 0.025% (and it's easier if we just leave it in percent).
Then 180-x = amount of the 0.1%.

0.025x + (180-x)*0.1 = 180*0.05
Solve for x and 180-x

I've estimated this will be 120 of the 0.025% and 60 of the 0.1% to give 180 of 0.05% but you should confirm all of this.