Incorrect. Use the formula and fill in the known values: $\displaystyle{100},{000}={100}{{\left({100}\right)}}^{{\frac{{t}}{{40}}}}\usepackage{cmbright}\Huge\$

Divide both sides by 100 and then take logarithms of both sides. Use the power property of logarithms to simplify. Evaluate the logarithms and solve for t. The correct answer is 60.