A plane flies between 4 cities; A, B, C and D. Passengers board and alight at each airport in every city when it departs and lands, respectively.  The distance between city A and city B is 100 miles.  The distance between city B and city C is 50 miles more than the distance between city A and city B.  The distance between city C and city D is twice the distance between city B and city C. Calculate the total distance between city A and city D.
How to solve this?