Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
497 views
in Distance, Time and Speed by (49.2k points)
closed by

A train travelling at 36 km/hr passes in 12 seconds another train half its length, travelling in the opposite direction at 54 km/hr. If it also passes a railway platform in \(1\frac12\) minutes, what is the length of the platform? 

(a) 800 m 

(b) 700 m 

(c) 900 m 

(d) 1000 m

1 Answer

+1 vote
by (46.2k points)
selected by
 
Best answer

(b) 700 m

Let the length of the first train be x metres. 

Then, length of the second train = \(\frac{x}{2}\) metres 

Relative speed = (36 + 54) km/hr = 90 km/h

\(\big(90\times\frac5{18}\big)\) m/s = 25 m/s

∴ \(\frac{x+\frac{x}2}{25}=12\)  ⇒ \(\frac{3x}{2} = 300 \)  ⇒ \(x\) = 200.

∴ Length of the first train = 200 m. 

Let the length of the platform be y metres. 

Speed of the first train = \(\big(36\times\frac5{18}\big)\) m/s = 10 m/s

∴ (200 + y) x \(\frac1{10}\) = 90

⇒ 200 + y = 900 ⇒ y = 700 m.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...