Question

R=log(I/Io)
R is the Richter number of the earthquake, I is the intensity of the earthquake, and Io is the intensity of the minimum detectable earthquake.
Please help! An earthquake has a Richter number of 4.2. How many times more intense than the minimum detectable earthquake is the earthquake? Round your answer to the nearest whole number.

Answer 1

\[R = 4.2\]
and the answer you are looking for is:
\[\frac{I}{I_0}\]
You want a ratio of the intensity to the minimum detectable intensity (you want the value of that fraction).
so you want to solve:
\[4.2 = \log\bigg(\frac{I}{I_0}\bigg)\]
for the fraction. your answer should be something like
\[\frac{I}{I_0} = number\]