Two delivery cars start from the same warehouse at the same time in identical directions. The first tracks a constant speed of 45 km/h and the second runs at 55 km/h. What is the distance between them after 2 hours 30 minutes? MCQ with Answer and Explanation
Two delivery cars start from the same warehouse at the same time in identical directions. The first tracks a constant speed of 45 km/h and the second runs at 55 km/h. What is the distance between them after 2 hours 30 minutes?
A. 25 km
B. 27 km
C. 30 km
D. 22 km
Answer: Option A
Solution (By JKSSB Mock Tests)
Relative speed = 55 - 45 = 10 km/h. Time = 2.5 hours. Distance separation = Relative Speed * Time = 10 * 2.5 = 25 km.
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 person has to cover a distance of 160 km. He covers the first half of the distance at 40 km/h. At what speed must he travel the remaining half to make the average speed for the whole journey 50 km/h?
Explanation:
Let the required speed for the second half be x km/h. Using the average speed formula for equal halves: Average Speed = 2v1*v2 / (v1 + v2) => 50 = (2 * 40 * x) / (40 + x) => 50(40 + x) = 80x => 2000 + 50x = 80x => 30x = 2000 => x = 66.67 km/h.
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