The figure shows two vertical plates of the capacitor at the distance of 3.0 millimeters. The plate of 0 volts is to the left of the plate of 300 volts. The space between plates is divided by 2 vertical dashed lines on 3 equal parts. The potential of the left line is equal to 100 volts. The potential of the right line is equal to 200 volts. What is the electric field strength inside the capacitor?