Solved UPSC CDS/OTA Question
A solved UPSC CDS/OTA PYQ — decoded step-by-step.
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Trains leave station A for another station B after a gap of every one hour, while trains leave station B for station A also after a gap of every one hour. Each train takes 4 hours. To complete the journey. Trains leave stations A and B simultaneously after an interval of every one hour. If a person starts from station A for station B, how many trains will be crossed before arriving at station B?
Step-by-Step Solution
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A total of 7 trains started from B across from station A .
Sol. Suppose the train starts at 4 pm from station A then it will reach B at 8 pm. Any train starting between this time interval or it is on the way between this time interval will cross the train starting from A at 4 pm.
Trains started from B at 1 pm, 2pm, 3pm, 4pm, 5pm, 6pm, 7pm will meet the train on its way to (b)