A car travels the first half of a total distance at speed v1 and the second half at speed v2. What is the expression for the average speed of the car? MCQ with Answer and Explanation

A car travels the first half of a total distance at speed v1 and the second half at speed v2. What is the expression for the average speed of the car?
A. v1*v2 / (v1 + v2)
B. (v1 + v2) / 2
C. 2v1*v2 / (v1 + v2)
D. 2 / (v1 + v2)
Answer: Option C
Solution (By JKSSB Mock Tests)
When equal distances are traveled at speeds v1 and v2, the average speed is the harmonic mean: 2v1*v2 / (v1 + v2).

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Practice More Time Speed and Distance Questions

Question #1
A locomotive express train passes a milestone column track point in 10 seconds flat. If the speed index of the train records at 54 km/h, find the length of the train layout.
A. 165 meters
B. 135 meters
C. 180 meters
D. 150 meters

Correct Answer: Option D


Explanation:
Speed of train = 54 * (5/18) = 15 m/s. Length of train layout = Speed * Time = 15 * 10 = 150 meters.

This question belongs to: Maths Time Speed and Distance
Question #2
A student walks from his quarter block to the academy center at 4 km/h and arrives 8 minutes late. If he manages a pace of 5 km/h, he arrives 4 minutes early. Find the track distance.
A. 5.0 km
B. 4.0 km
C. 4.5 km
D. 3.5 km

Correct Answer: Option B


Explanation:
Time difference = 8 - (-4) = 12 minutes = 10/60 = 1/5 hours. Let distance be d. d/4 - d/5 = 1/5 => d/20 = 1/5 => d = 4 km.

This question belongs to: Maths Time Speed and Distance
Question #3
A generic bullet train covers a distance between two stations in 2 hours 30 minutes at a speed of 120 km/h. How much time will it take to cover the same distance at a speed of 150 km/h?
A. 2.15 hours
B. 2.2 hours
C. 2 hours
D. 1.5 hours

Correct Answer: Option C


Explanation:
Distance = 120 * 2.5 = 300 km. Time at 150 km/h = 300 / 150 = 2 hours.

This question belongs to: Maths Time Speed and Distance