2 part question! 122.53 rounded to the nearest whole number.
18.59 rounded to the nearest whole number.

1.) 123  2.) 19

Step-by-step explanation:

Both of these numbers would round up since 5+ makes the number before itself add 1.

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:  

the anwser is x< -17/2