Question: If John invests $2300 in a savings account with a 6% interest rate compounded annually, how long will it take until John's account has a balance of $4150?

So, I have made two solution.

The first one is,

A(t)=B(1+r)^t

4150=2300(1.06)^t

t=10.129

The second one is,

Y=P x e^rt

4150=2300(e)^0.06t

e^0.06t=1.8043

ln1.8043=0.06t

t=9.837

So, I got two answer which are 10.129 and 9.837. The question is asking time so should I round up 10.129 so 11 yrs or round up 9.837 so 10 yrs?

What is the correct answer: 10yrs? 11yrs?