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. 3.0 hours
B. 2.5 hours
C. 3.5 hours
D. 4.0 hours
Answer: Option A
Solution (By JKSSB Mock Tests)
Upstream speed = 15 - 3 = 12 km/h. Time taken = Distance / Upstream speed = 36 / 12 = 3 hours.
A person covers a certain distance at a certain speed. If he reduces his speed by 20%, he takes 15 minutes more to cover the same distance. Find his usual time.
Explanation:
New Speed = 0.8 * Usual Speed. Since distance is constant, New Time = Usual Time / 0.8 = 1.25 * Usual Time. Increase in time = 0.25 * Usual Time = 15 minutes. Usual Time = 15 / 0.25 = 60 minutes.
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