Answer :
Given that the cost of an item increases by 2.5% each year.
Suppose that a jacket cost $100 in the year 2017.
Here,
[tex]\begin{gathered} P=100 \\ r=0.025 \end{gathered}[/tex]Suppose after n years, the cost of the jacket will be $600.
Then,
[tex]\begin{gathered} 600=100(1+0.025)^n \\ 6=(1.025)^n \end{gathered}[/tex]Taking logarithm of both sides,
[tex]\begin{gathered} \ln 6=n\ln (1.025) \\ n=\frac{\ln 6}{\ln (1.025)} \\ \approx72.6 \end{gathered}[/tex]By rounding to the nearest year, after 73 years the cost of the jacket will be $600.