CAT 2007 — QA Question 8
Answer the next 2 questions based on the information given below.
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.
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What is the time difference between A and B?
Answer & solution
- A
1 hour and 30 minutes
- B
2 hours
- C
2 hours and 30 minutes
1 hour
- E
Cannot be determined
Let the speed of the plane be x kmph.
Then the speed from B to A is (x – 50) kmph and that from A to B is (x + 50) kmph.
Note that the plane travels from B to A, halts for 1 hour and travels back to B, all in 12 hrs.
∴ 3000/(x – 50) + 1 + 3000/(x + 50) = 12
Solving this we get x = 550. [you can check options from the 2nd question of this set to figure out the value of x.]
Speed of plane = 550 kmph
Now, the plane takes 3000/500 = 6 hrs to travel from B to A.
It reaches A when the time at B is 8:00 am + 6 hrs = 2:00 p.m.
When plane reaches A, time at B is 2 p.m. while time at A is 3 p.m.
∴ The time difference between A and B is 1 hour.
Hence, option (d).