For the first question, you will write a ratio of 1/2 oz:10 pounds. Please see the attached picture. There are 9 groups of 10 oz in 90 oz, so you will need 9 groups of the amount of medicine too!
For the second question, you need to understand that the exponent (2^3) must be evaluated first because all forms of multiplication/ groupings comes first before adding or subtracting.
Exponents are a way of showing repeated multiplication, so it is done first.
