We know that 'the gross domestic product of the city in 2000 was \(\frac{3}{8}\) less than that in 2015 ,'so let's assume that the GDP in 2015 was 800 ; thus, the GDP in the year \(2000=800-\frac{3}{8} \times 800=500\).

We assumed a seemingly puzzling number '800' for the GDP in 2015 since we find that in the denominator of the fraction \(\frac{3}{8}\), we have to deal with ' 8, ' and ' 800 ' is a multiple of ' 8 ' - easy to deal with.

We know that the population year \(2000=2 \mathrm{M}\) and that in \(2015=2.5 \mathrm{M}\)

Thus,

Per capita GDP in \(2000=\frac{\text { GDP }}{\text { population }}=\frac{500}{2 \mathrm{M}}=\frac{250}{\mathrm{M}}\) and

Per capita GDP in \(2005=\frac{\text { GDP }}{\text { population }}=\frac{800}{2.5 \mathrm{M}}=\frac{8000}{25 \mathrm{M}}=\frac{320}{\mathrm{M}}\)

Thus,

\[

\begin{aligned}

& \text { Change in Per Capita GDP over 2000-2015 }=\frac{\text { (Per Capita GDP in 2015)-(Per Capita GDP in 2000) }}{\text { (Per Capita GDP in 2000) }} \times 100 \% \\

& =\frac{\frac{320}{\mathrm{M}}-\frac{250}{\mathrm{M}}}{\frac{250}{\mathrm{M}}} \times 100 \% \\

& =\frac{70}{250} \times 100 \% \text { (M gets cancelled) } \\

& =28 \%

\end{aligned}

\]