XAT 2019 — QA & DI Question 21
Answer the next 3 questions based on the information given below.
Given below is the time table for a trans-continental train that cuts across several time zones. All timings are in local time in the respective cities. The average speed of the train between any two cities is the same in both directions.
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Which of the following pairs of cities are in the same time zone?
Answer & solution
- A
Vaq and Sab
- B
No pair of cities are in the same time zone.
- C
Sab and Raz
- D
Sab and Raz
Zut and Yag
When travelling between 2 cities in different time zones, the actual travelling time is the average of two time taken both ways between the cities when calculated on local basis.
Also, the time difference between the two cities is half of difference of time taken both ways between the cities when calculated on local basis.
Let’s take the example of journey between Vaq and Yag.
Time taken to go from Vaq to Yag, on local basis (11:55 pm to 10:50 am) = 10 hours 55 mins.
Time taken to go from Yag to Vaq, on local basis (7:50 am to 2:45 pm) = 6 hours 55 mins.
∴ The actual travelling time between Yag and Vaq is average of 10 hours 55 mins and 6 hours 55 mins i.e., 8 hours 55 mins.
Also, the time difference between the two cities is half of (10 hours 55 mins - 6 hours 55 mins) i.e., 2 hours.
Similarly, we can calculate the travelling time and time difference between all the cities.
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From the table we can see that Zut and Yag are in the same time zone.
Hence, option (e).