A person row a boat 16 km upstream in 4 hours. If the speed of the current is 1 km/h, find the speed of the boat in still water. MCQ with Answer and Explanation
A person row a boat 16 km upstream in 4 hours. If the speed of the current is 1 km/h, find the speed of the boat in still water.
A. 5 km/h
B. 4 km/h
C. 7 km/h
D. 6 km/h
Answer: Option A
Solution (By JKSSB Mock Tests)
Upstream speed = 16 / 4 = 4 km/h. Upstream Speed = Speed in still water - Current speed => 4 = Speed in still water - 1 => Speed in still water = 5 km/h.
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.
A regular passenger bus tracks a route divided into three equal segments. It runs the segments at 20 km/h, 30 km/h, and 60 km/h respectively. Find the average speed across the whole route.
Explanation:
Let each segment distance be 60 km. Total distance = 3 * 60 = 180 km. Total time = 60/20 + 60/30 + 60/60 = 3 + 2 + 1 = 6 hours. Average speed = 180 / 6 = 30 km/h.
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