Navigation LORAN (long distance radio navigation) for aircraft and ships uses synchronized pulses transmitted by widely separated transmitting stations. These pulses travel at the speed of light $(186,000$ miles per second). The difference in the times of arrival of these pulses at an aircraft or ship is constant on a hyperbola having the transmitting stations as foci. Assume that two stations, 300 miles apart, are positioned on a rectangular coordinate system at $(-150,0)$ and $(150,0)$ and that a ship is traveling on a path with coordinates $(x, 75)$ (see figure). Find the $x$ -coordinate of the position of the ship when the time difference between the pulses from the transmitting stations is 1000 microseconds $(0.001$ second $)$ .