Subject: General Aptitude · Chapter: Problems on Trains · Exam: · Marks: · Difficulty:
A train crosses another train running in the opposite direction in x seconds. What is the speed of the train? (S.B.I.P.O., 2003) I. Both the trains have the same length and are running at the same speed. II. One train crosses a pole in 5 seconds.
Answer
SELF-PRACTICE — the source book printed no answer.
Nothing is invented here, so this question has no answer on record.
Explanation
Let the two trains of length a metres and b metres be moving in opposite directions at u m / s and v m / s. Time taken to cross each other ( a + b) ( a + a) a = m/sec ⇒ x = = . ...(i) (u + v ) (u + u) u QUANTITATIVE APTITUDE Time taken to cross the pole Length of the train a a = = ⇒ =5 ...(ii) Speed of the train u u From (i) and (ii) also, we cannot find u. ∴ The correct answer is (d).
Explanation as extracted from the printed page; notation may be imperfect.