#4: Which property could be used to solve the equation below? *
15 = x + 13

15-13=2

13+2=15

x=2

now double check the answer and

2+13=15

x = 2 is your answer

answer: it is 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

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