A sedan covers a distance path of 480 km at a uniform tracking speed. If the speed index is lowered by 10 km/h, the trip records 2 hours longer. Find the original baseline speed. MCQ with Answer and Explanation
A sedan covers a distance path of 480 km at a uniform tracking speed. If the speed index is lowered by 10 km/h, the trip records 2 hours longer. Find the original baseline speed.
A. 50 km/h
B. 55 km/h
C. 60 km/h
D. 45 km/h
Answer: Option A
Solution (By JKSSB Mock Tests)
Let original speed be s. 480 / (s - 10) - 480 / s = 2 => 240 / (s - 10) - 240 / s = 1 => 2400 = s(s - 10). Solving s^2 - 10s - 2400 = 0 gives (s - 50)(s + 40) = 0. Baseline speed = 50 km/h.
A motorboat registers a speed of 14 km/h in still water. If the river current tracks at 2 km/h, find the duration required to complete a 48 km downstream course.
The speeds of two cars are in the ratio 5 : 4. If they cover the same distance, and the slower car takes 2.5 hours, how much time does the faster car take?
Explanation:
Ratio of speeds = 5:4, so ratio of times taken = 4:5. The slower car corresponds to 5 parts = 2.5 hours => 1 part = 0.5 hours. Time for the faster car = 4 parts = 4 * 0.5 = 2 hours.
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