In Japan, the Earthquake Early Warning (EEW) is a warning issued when an earthquake is detected by multiple seismometers. When a P - wave is detected from two (or more) of the 4, 235 seismometers installed throughout Japan, the JMA analyzes and predicts the approximate location of the earthquake's epicenter. This allows the JMA to notify peopl in affected prefectures by TV and radio if a strong earthquake is expected.Using reasonable assumptions for seismic wave velocities, calculate how much time this warning system could provide residents in a city 200 km from the epicenter to take safety measures before shear waves arrive.