Astraight railroad track is being built to connect two cities. the measured distance of the track between the two cities is 160.5 miles. a mailstop is 28.5 miles from the first city. how far is the mailstop from the second city?

Let point A be 0.0 miles (first city)
Let point B be 160.5 miles (first city to second city)
Let point C be 28.5 miles (first city to mail stop)

Take C – A = C [28.5 - 0.0 = 28.5] (This checks the distance between city 1 and Mail stop) 

Then Take B – C = Distance from the first city to the second city [160.5 - 28.5 = 132 Miles]

The Mail stop is 132 miles from the Second City.