A person invests 1000 dollars in a bank. The bank pays 6% interest compounded annually. To the nearest tenth of a year, how long must the person leave the money in the bank until it reaches 2100 dollars?

Solution
For this case we have the following information given:
A= 1000
r= 0.06
n = 1
A= 2100
So we can set up the following formula:
[tex]2100=1000(1+\frac{0.06}{1})^t[/tex]We can solve for t on this way:
[tex]\ln (\frac{2100}{1000})=t\cdot\ln (1.06)[/tex]Solving for t we got:
[tex]t=\frac{\ln (2.1)}{\ln (1.06)}=12.73[/tex]Rounded to the nesrest tenth we got:
12.7 years