Given below is the real number corresponding to the midpoint M of the segment PQ. Also given is the real number corresponding to one of the endpoints. Find the real number corresponding to the other endpoint.

Sound travels about 750 miles per hour. a) suppose it takes about 1.5 seconds to hear the echo. how far away is the canyon wall, in feet? for this i got 825 ft b) suppose you stand 1,925 feet from the canyon wall and sound the horn. how long will it take to hear the echo? (i'm stuck on this)