Two stations A and B are 450 km apart. A train leaves station A at 4:00 PM at 60 km/h. Another train leaves station B at 5:00 PM at 70 km/h traveling towards A. At what time will they meet? MCQ with Answer and Explanation
Two stations A and B are 450 km apart. A train leaves station A at 4:00 PM at 60 km/h. Another train leaves station B at 5:00 PM at 70 km/h traveling towards A. At what time will they meet?
A. 8:00 PM
B. 8:30 PM
C. 7:30 PM
D. 9:00 PM
Answer: Option A
Solution (By JKSSB Mock Tests)
By 5:00 PM, the first train has traveled for 1 hour and covered 60 km. Distance left between them = 450 - 60 = 390 km. Relative speed = 60 + 70 = 130 km/h. Time to meet after 5:00 PM = 390 / 130 = 3 hours. Meeting time = 5:00 PM + 3 hours = 8:00 PM.
A person row a boat 12 km downstream in 1 hour. If the river current flows at 3 km/h, find the time taken by the boat to row the same distance upstream.
Explanation:
Downstream speed = 12 / 1 = 12 km/h. Baseline boat speed in still water = Downstream speed - Current speed = 12 - 3 = 9 km/h. Upstream speed = Still water speed - Current speed = 9 - 3 = 6 km/h. Time taken upstream = Distance / Upstream speed = 12 / 6 = 2 hours.
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