Answer: Hello your question is quite vague but i will provide a general answer within the scope of your company
answer : D = Y + Z
Explanation:
Moving from city W to city x
Given that there is a milestone at the beginning of the journey ( i.e. at City W )
and Another milestone is Located between City W and City X after traveling for time T
lets assume
distance between Milestone at W and milestone between W and x = Y
distance between City x and milestone between City W and City x = Z
Finally to determine the Distance between City x and city W
D = Y + Z