Correct. Use the formula and fill in the known values: $\displaystyle{1},{000},{000}={1},{000}{{\left({10}\right)}}^{{\frac{{t}}{{50}}}}\usepackage{cmbright}\Huge\$

Divide both sides by 1,000: $\displaystyle{1},{000}={{\left({10}\right)}}^{{\frac{{t}}{{50}}}}\usepackage{cmbright}\Huge\$

Take logarithms and use the power property: $\displaystyle{\log{{1}}},{000}={{\log{{\left({10}\right)}}}}^{{\frac{{t}}{{50}}}}={\left(\frac{{t}}{{50}}\right)}{\log{{10}}}\usepackage{cmbright}\Huge\$

Evaluate the logarithms: $\displaystyle{3}={\left(\frac{{t}}{{50}}\right)}{\left({1}\right)}\usepackage{cmbright}\Huge\$ , so $\displaystyle{t}={150}\usepackage{cmbright}\Huge\$