Bunuel
Cities A and B are in different time zones. A is located 3000 km east of B. The table below describes the schedule of an airline operating non-stop flights between A and B. All the times indicated are local and on the same day.

Assume that planes cruise at the same speed in both directions. However, the effective speed is influenced by a steady wind blowing from east to west at 50 km per hour.
What is the plane’s cruising speed in km per hour?
(A) 500
(B) 550
(C) 600
(D) 700
(E) Cannot be determined
Are You Up For the Challenge: 700 Level QuestionsAlright, total time 7+4=11 hrs.
The problem is similar to boat and stream-related ones.
Let the speed of the plane be x km/hr. Wind blowing from East to West at 50 km/hr.
So downstream speed i.e. East to West i.e. A to B is (x+50). Upstream speed i.e. West to East i.e. B to A is (x-50).
Speed=Distance/Time or, Time=Distance/Speed.
Total time 3000/(x+50) + 3000/(x-50) which is equal to 11 hrs.
Put the options given and check. x=550 matches so correct answer is (B).