A car travels a distance of 360 km at a uniform speed. If the speed is reduced by 10 km/h, it takes 2 hours longer. Find the original speed. MCQ with Answer and Explanation
A car travels a distance of 360 km at a uniform speed. If the speed is reduced by 10 km/h, it takes 2 hours longer. Find the original speed.
A. 45 km/h
B. 55 km/h
C. 40 km/h
D. 50 km/h
Answer: Option A
Solution (By JKSSB Mock Tests)
Let original speed be s. 360 / (s - 10) - 360 / s = 2 => 180 / (s - 10) - 180 / s = 1 => 180(10) = s(s - 10) => 1800 = s(s - 10). Solving s^2 - 10s - 1800 = 0 gives (s - 45)(s + 40) = 0. Since speed is positive, s = 45 km/h.
A dispatch rider travels between two depots at a speed of 50 km/h and arrives on schedule. If he travels at 40 km/h, he is late by 45 minutes. Find the distance between the two depots.
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