Aptitude Discussion

Q. |
A good train and a passenger train are running on parallel tracks in the same direction. The driver of the goods train observes that the passenger train coming from behind overtakes and crosses his train completely in 60 sec. Whereas a passenger on the passenger train marks that he crosses the goods train in 40 sec. If the speeds of the trains be in the ratio 1:2. Find the ratio of their lengths. |

✖ A. |
$3 : 1$ |

✔ B. |
$2:1$ |

✖ C. |
$3 : 2$ |

✖ D. |
$4 : 3$ |

**Solution:**

Option(**B**) is correct

Let the speeds of the two trains be $s$ and 2s m/s respectively.

Also, suppose that the lengths of the two trains are $P$ and $Q$ metres respectively.

Then,

\(\dfrac{P+Q}{2s-s}=60\)------(1)

and

\(\dfrac{P}{2s-s}=40\)------(2)

On dividing these two equation we get:

\(\dfrac{P+Q}{P}=\dfrac{60}{40}\)

$P:Q$ = **2 : 1**

**Shikha Bharti**

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**Akshay**

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I think this solution is wrong as the person in passenger train also moving with 2s and as per the question "Whereas a passenger on the passenger train marks that he crosses the goods train in 40 sec." so it implies length of train according to him should be the length of goods train nor the passenger train + goods train .please check its option should be (C)3:2

Not able to solve. Pls help me akshay..

Not able to solve. Pls help me akshay. #shikha