It takes the high-speed train x hours to travel the z miles from town a to town b at a constant rate, while it takes the regular train y hours to travel the same distance at a constant rate. if the high-speed train leaves town a for town b at the same time that the regular train leaves town b for town a, how many more miles will the high-speed train have traveled than the regular train when the two trains pass each other?
(a) z(y – x)/x + y
(b) z(x – y)/x + y
(c) z(x + y)/y – x
(d) xy(x – y)/x + y
(e) xy(y – x)/x + y