Subject: General Aptitude · Chapter: Problems on Trains · Exam: 2009 · Marks: · Difficulty:
A train travelling with constant speed crosses a 90 m long platform in 12 seconds and a 120 m long platform in 15 seconds. Find the length of the train and its speed.
Answer
Answer (as printed):
Explanation
Let the length of the train be x metres. x + 90 x + 120 Then, = ⇔ 15 ( x + 90) = 12 ( x + 120) 12 15 ⇔ 15x + 1350 = 12x + 1440 ⇔ 3x = 90 ⇔ x = 30. 30 + 90 18 Speed of the train = m/sec = 10 m/sec = 10 × km/hr = 36 km/hr. 12 5 Hence, lenght of train = 30 m, speed of train = 36 km/hr.
Explanation as extracted from the printed page; notation may be imperfect.