A person covers a certain distance at a certain speed. If he reduces his speed by 20%, he takes 15 minutes more to cover the same distance. Find his usual time. MCQ with Answer and Explanation
A person covers a certain distance at a certain speed. If he reduces his speed by 20%, he takes 15 minutes more to cover the same distance. Find his usual time.
A. 50 minutes
B. 60 minutes
C. 75 minutes
D. 80 minutes
Answer: Option B
Solution (By JKSSB Mock Tests)
New Speed = 0.8 * Usual Speed. Since distance is constant, New Time = Usual Time / 0.8 = 1.25 * Usual Time. Increase in time = 0.25 * Usual Time = 15 minutes. Usual Time = 15 / 0.25 = 60 minutes.
A car travels a distance of 240 km at a certain speed. If the speed is increased by 10 km/h, it takes 4 hours for the journey. Find the original speed.
A man can walk a certain distance in 6 hours and ride back in 2 hours. If he rides both ways, he will save 2 hours. How much time will he take if he walks both ways?
Explanation:
Let W be walking time one way and R be riding time one way. W + R = 6 + 2 = 8 hours (total trip: walk one way, ride back). If he rides both ways, total time is 2R. He saves 2 hours, so 2R = 8 - 2 = 6 hours => R = 3 hours. From W + R = 8, W = 5 hours. Walking both ways takes 2W = 10 hours.
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