Consider the expression 20 (4^2/ 2). How many terms does it have? Identify them. Also, identify a quotient in the expression.

she will travel a distance in the range of 3 - 11 miles

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:  

a is the best answer choice