A vehicle covers a lap distance of 450 km at a uniform speed. If its velocity is cut by 15 km/h, the trip maps 1.5 hours longer. Find the original speed. MCQ with Answer and Explanation

A vehicle covers a lap distance of 450 km at a uniform speed. If its velocity is cut by 15 km/h, the trip maps 1.5 hours longer. Find the original speed.
A. 75 km/h
B. 80 km/h
C. 90 km/h
D. 60 km/h
Answer: Option A
Solution (By JKSSB Mock Tests)
Let original speed be s. 450/(s-15) - 450/s = 1.5 => 300/(s-15) - 300/s = 1 => 300(15) = s(s-15) => 4500 = s(s-15). Solving s^2 - 15s - 4500 = 0 gives (s-75)(s+60) = 0. Baseline speed = 75 km/h.

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Practice More Time Speed and Distance Questions

Question #1
A cyclist covers a 3.6 km track in 12 minutes. Find his speed in meters per second.
A. 5 m/s
B. 8 m/s
C. 6 m/s
D. 4 m/s

Correct Answer: Option A


Explanation:
Distance = 3.6 km = 3600 meters. Time = 12 minutes = 720 seconds. Speed = 3600 / 720 = 5 m/s.

This question belongs to: Maths Time Speed and Distance
Question #2
A runner tracks a circular field loop course of radius 70 meters. If his speed registers at 20 m/s, find the total loop rounds completed by him in 2 minutes 12 seconds.
A. 6 rounds
B. 8 rounds
C. 5 rounds
D. 7 rounds

Correct Answer: Option A


Explanation:
Circumference = 2 * (22/7) * 70 = 440 meters. Time = 2 minutes 12 seconds = 132 seconds. Total distance wrapped = Speed * Time = 20 * 132 = 2640 meters. Number of loop rounds completed = 2640 / 440 = 6 rounds.

This question belongs to: Maths Time Speed and Distance
Question #3
A man can row 8 km/h in still water. He takes 4 hours to row to a point and back when the current flows at 4 km/h. How far is the point?
A. 10 km
B. 16 km
C. 14 km
D. 12 km

Correct Answer: Option D


Explanation:
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.

This question belongs to: Maths Time Speed and Distance