Addison's budget is shown in the
circle graph below. her total monthly
budget is $3,500. how much does
addison spend on rent?
rent
30%
other
15%
savings
30%
groceries
25%

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:  

1/4 is the answer if i recall correctly.

the circumference is c≈245.04