please provide solution/ process

Use the following information to answer the next question. Earthquake intensity, I, is given by the equation I = 10(10)", where m is the magnitude measured to the nearest tenth on the Richter scale and lo is the reference intensity. In 1906, the San Francisco Bay area had an earthquake with a magnitude of 7.8 on the Richter scale. 4. What is the magnitude of an earthquake that is 158 times less intense than the 1906 San Francisco Bay earthquake