Four cities P, Q, R and S are connected through one-way routes as shown in the…

GATE · 2022 · AE · General AptitudeGATE · 2022 · GE · General AptitudeGATE · 2022 · ME · Set 2 · General Aptitude

Four cities P, Q, R and S are connected through one-way routes as shown in the figure. The travel time between any two connected cities is one hour. The boxes beside each city name describe the starting time of first train of the day and their frequency of operation. For example, from city P, the first trains of the day start at 8 AM with a frequency of 90 minutes to each of R and S. A person does not spend additional time at any city other than the waiting time for the next connecting train.

If the person starts from R at 7 AM and is required to visit S and return to R, what is the minimum time required?

Four cities at corners of a square: P upper left, Q upper right, R lower left, S lower right. Directed arrows run Q to P across the top, P to R down the left, S to R across the bottom, S to Q up the right, R to Q on the rising diagonal and P to S on the falling diagonal. Adjacent two-cell boxes give P: 8 AM, 90 min; Q: 5 AM, 120 min; R: 7 AM, 60 min; S: 8 AM, 45 min. Diagonal lines cross without a marked city at the crossing.

A.
6 hours 30 minutes
B.
3 hours 45 minutes
C.
4 hours 30 minutes
D.
5 hours 15 minutes

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