A person can row 8 km/h in still water. If the river current flows at 4 km/h, it takes him 4 hours to row to an outpost and back. Find the distance of the outpost. MCQ with Answer and Explanation
A person can row 8 km/h in still water. If the river current flows at 4 km/h, it takes him 4 hours to row to an outpost and back. Find the distance of the outpost.
A. 12 km
B. 16 km
C. 14 km
D. 10 km
Answer: Option A
Solution (By JKExamLibrary)
Downstream speed = 8 + 4 = 12 km/h. Upstream speed = 8 - 4 = 4 km/h. Let distance be d. d / 12 + d / 4 = 4 => 4d / 12 = 4 => d = 12 km.
A delivery sedan logs a trip of 240 km at an average speed of 60 km/h. It travels the first 120 km at 40 km/h. Find the speed for the remaining 120 km.
Explanation:
Total time for full trip = 240 / 60 = 4 hours. Time spent on first 120 km = 120 / 40 = 3 hours. Remaining time for the last 120 km = 4 - 3 = 1 hour. Required speed = 120 km / 1 hour = 120 km/h.
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