A = 800(1.055)^x

Question

suppose $800 is deposited into an account that pays 5.5% per year, compounded anually. the amount in the account A, is given by the equation a= 800(1.055)^x, where x is the number of years the money is in the account. Approximately how many years will it take for themoney to double in value.

Answer 1

so,if you start with 800, then double = 1600

1600 = 800 (1.055)^x

divide by 800

2 = 1.055^x

take log of both sides

log(2) = x log(1.055)

x = log(2)/log(1.055)    

x = 12.946