A research shows that the Richter scale magnitudes of earthquakes are normally distributed with a mean of 1.67 and a standard deviation of 0.385. Earthquakes with magnitudes less than 2.00 are considered "microearthquakes" that humans do not feel. What percentage of earthquakes fall into this category?

Student's partially finished answer:

We need to find the probability that earthquakes fall into the microearthquake category. The first step is to find the probability that the Richter scale is less than 2.00.