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]
Answer: The Mail stop is 132 miles from the Second City.