A boat can row 15 km/h in still water. If the velocity index of the stream tracks at 3 km/h, find the time parameter taken by the boat to row 36 km upstream. MCQ with Answer and Explanation
A boat can row 15 km/h in still water. If the velocity index of the stream tracks at 3 km/h, find the time parameter taken by the boat to row 36 km upstream.
A. 2.5 hours
B. 3.0 hours
C. 3.5 hours
D. 4.0 hours
Answer: Option B
Solution (By JKSSB Mock Tests)
Upstream speed = 15 - 3 = 12 km/h. Time taken = Distance / Upstream speed = 36 / 12 = 3 hours.
A car driver leaves Bangalore at 8:30 AM and expects to reach a place 300 km away at 12:30 PM. At 10:30 AM he finds that he has covered only 40% of the distance. By how much must he increase the speed of the car to reach on scheduled time?
Explanation:
Total time available = 4 hours. At 10:30 AM (after 2 hours), distance covered = 40% of 300 = 120 km. Remaining distance = 180 km. Remaining time = 12:30 PM - 10:30 AM = 2 hours. Required speed = 180 / 2 = 90 km/h. Original speed = 120 / 2 = 60 km/h. Increase in speed = 90 - 60 = 30 km/h.
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