Solution to 1986 Problem 39


We assume a relationship of the form
\begin{align*} \log_{10} G = m \log_{10} \omega + b\end{align*}
and attempt to calculate m. Raising 10 to the power of both sides, we see that G = 10^b\omega^m, so finding m will allow us to distinguish between answers (B), (C), (D), and (E). From the two points (3 \cdot 10^5, 10^2) and (2 \cdot 10^5, 2 \cdot 10^2), we find that
\begin{align*}m = - \frac{\log_{10} \left(2\right)}{\log_{10} \left(3/2\right)} = - \frac{\log_{2} \left(2\right)}{\log_{2} \...
Since (3/2)^2 = 9/4 \approx 2, 1/2 provides a better approximation to \log_2 \left(3/2\right) than 1. Therefore,
\begin{align*}m \approx -2\end{align*}
and answer (E) is correct.


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