URGENT ANSWER NEEDED:
create an exponential function : y=a times b^x

you invest 200 dollars when you are 18 years old. If left untouched, you are told to expect the money to double every five years

he earned 78.75 in interest.

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:  

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