How much would 500$ invested at 5% interest compounded continuously be worth after 8 years

It will be worth $745.89 assuming compounding 365 times per year. The formula for compound interest is 
A = P * (1 + (r/n))^(nt) 
A = total return of both principal and interest 
P = principal invested ($500) 
r = interest rate expressed as a decimal (.05) 
n = number of compounding periods per year (365) 
t = time in years (8)
thus the answer is $754.89

Ais the answer to your ques