Civil Services Examination · Question 69
A train has to complete a journey of 800 km. If it meets a minor accident, its speed becomes half of the existing speed. If there is a mechanical defect, the speed becomes one-fourth of the existing speed. On its way, the train meets with a minor accident after 200 km; and 400 km thereafter, it develops a mechanical defect. Had the train developed the mechanical defect after 200 km and met the minor accident 400 km thereafter, it would have taken 4 more hours to reach its destination. What was the original speed of the train in km per hour?
Show answer & explanation
Answer: (A) 200
Explanation
Actual: 200/v + 400/(v/2) + 200/(v/8) = 2600/v. Hypothetical: 200/v + 400/(v/4) + 200/(v/8) = 3400/v. The difference 800/v = 4, so v = 200 km/h.