A GPS receiver located at ground level simultaneously detects signals from three ground-based transmitters. The first signal, originating from Shenandoah University in Winchester, is decoded to read "the time is 10:12:07.612040". The second signal, originating from Thomas Jefferson's Poplar Forest, is decoded to read "the time is 10:12:07.612137". The last signal, originating from the Virginia State Capitol Building in Richmond, is decoded to read "the time is 10:12:07.612131". At the moment of reception, the receiver clock reads 10:12:07.612503 (which is, of course, incorrect). Assume that the speed of light is precisely 300,000 km/s. Ignore the curvature of the earth.
(a) What is the correct time at the receiver (to within 1 micro second)?
(b) What is the distance (to within 0.1 km) of the receiver to each of the transmitters?
(c) Where is the receiver located (nearest major landmark)?