Incorrect. Regroup: $\displaystyle{\left(\frac{{1.5}}{{5}}\right)}{\left(\frac{{{10}}^{{8}}}{{{10}}^{{4}}}\right)}\usepackage{cmbright}\Huge\$

Divide the numbers and convert into scientific notation. Use the quotient rule. Then regroup the powers of 10 and use the product rule. The population density per square mile is $\displaystyle{3}\times{{10}}^{{3}}\usepackage{cmbright}\Huge\$ . The correct answer is 3.