I just need a little help with this question and I couldn't find a decent answer that wasn't confusing. Thanks :) Find the missing angle: 114° 137° 48° to X= degrees​

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 the answer is b x = 1, y = 35/2