in Quantitative Aptitude edited by
421 views
0 votes
0 votes

A $300$ metre long metro train crosses a platform in a metro station in $39$ seconds while it crosses a lamp post in $18$ seconds. What is the length of the platform?

  1. $250$ metre
  2. $350$ metre
  3. $520$ metre
  4. $300$ metre 
in Quantitative Aptitude edited by
12.0k points
421 views

1 Answer

0 votes
0 votes
Lets say length of platform is $\text{L metre}.$

We know that $\text{Speed} = \dfrac{\text{Distance}}{\text{Time}}$

$S_{\text{train}} = \dfrac{300}{18}\;\text{metre/sec} = \dfrac{50}{3}\;\text{metre/sec} $

$S_{\text{train}} = \dfrac{300 + L}{39}\;\text{metre/sec}$

$ \implies \dfrac{50}{3} = \dfrac{300 + L}{39}$

$\implies 300 + L = 50 \times 13 = 650$

$\implies L = 350\;\text{metre}.$

So, the correct answer is $(B).$
12.0k points
Answer:

Related questions

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true