An open-top box with a square base is to have a volume of exactly 1,372 cubic inches. Find the dimensions (in inches) of the box that can be made with the smallest amount of materials.

d

step-by-step explanation:

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

i think you would have to divide the money he had saved, which is $2,000 by the time he plans on exercising which is 40 hours, and the answer you get should tell you the answer to your question.