Question
The train service was disrupted due to an accident after
a travel of 30 km. The speed was reduced to four-fifths of the original speed. This caused a delay of 45 min. If the accident had happened 20 km farther, it would have been running late for 36 min. What was the original speed of the train?Solution
Let the speed of the train be x. We know that. ⇒ Speed = Distance/Time Speed after accident = 4/5 of x = 4x/5 According to the question, The time difference in covering 20 km due to change in speed = 45 - 36 = 9 min 20/(4x/5) -(20/x) =9/60 100/4x)-20/x=9/60 ⇒ x = 33.33 km/h ∴ The original speed of the train is 33.33 Km/h.
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