The speed of a train is 25% more than the speed of a car. Both start from city P at the same time and reach city Q, 150 km away, at the same time. On the way, the train stops for 15 minutes at various stations. What is the speed of the car? MCQ with Answer and Explanation
The speed of a train is 25% more than the speed of a car. Both start from city P at the same time and reach city Q, 150 km away, at the same time. On the way, the train stops for 15 minutes at various stations. What is the speed of the car?
A. 140 km/h
B. 100 km/h
C. 120 km/h
D. 150 km/h
Answer: Option C
Solution (By JKSSB Mock Tests)
Let car speed be c, then train speed is 1.25c. Time difference = 150/c - 150/(1.25c) = 15/60 hour = 1/4 hour. 150/c * (1 - 1/1.25) = 1/4 => 150/c * (0.25/1.25) = 1/4 => 150/c * (1/5) = 1/4 => 30/c = 1/4 => c = 120 km/h.
A boatman can row 16 km/h in still water. If the river velocity index tracks at 4 km/h, find the time interval required by the boat hull to row 48 km upstream.
Explanation:
New speed = 6/7 of typical speed => New time = 7/6 of typical time. Difference = 1/6 of typical time = 14 minutes. Typical time = 14 * 6 = 84 minutes.
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