conversations.from: human
conversations.value: 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?
conversations.from: assistant
conversations.value: Since the distance between city A and B is 100 miles, and city B and C are 50 more miles apart than city A and B, then city B and C are 100+50 = 150 miles apart.
  The plane's total flying distance between cities A and C is 100+150= 250 miles.
  The distance between city C and city D is twice the distance between city B and city C, meaning city C and city D are 2*150 = 300 miles apart.
  The plane flies a distance of 250+300 = 550 miles from city A to city D.