Question

Tina wants to save money for school. Tina invests $1,100 in an account that pays an interest rate of 7.25%. How many years will it take for the account to reach $6,600? Round your answer to the nearest hundredth.

Answer 1

The amount of Tina money can be expressed in an exponent function like this:
an= $1100(1.0725)^n
The variable an represent the total money and variable n is the years needed to achieve that amount.

Then, the time needed for the money to reach $6,600 would be:

an= $1100(1.0725)^n
$6,600= $1100(1.0725)^n
$1,100(6)= $1100(1.0725)^n
6= (1.0725)^n
n= log1.075 6
n= 24.78