Alright, so let's look at the variables that we have already.
We have P (1500)
We have R (6.75%, .0675 in decimal form)
And, we have A (7300).
So, let's plug this into the formula
A=P(1+r)^t
7300=1500(1.0675)^t
/1500 /1500
4.866...=1.0675^t
Logarithms are the inverse of exponents, (if y=b^x then logarithm with base b of y =x)
So, we know that
t=logbase1.0675(4.866666)
can also put into your calculator as
t= (log4.8666)/(log1.0675)
Thus:
t=24.22569158
This rounds to (in hundredths)
24.23 years.
Looks like a minor rounding issue is all.