CAT 2020 Slot 2 QA Question 16: The distance from B to C is thrice that from A to B. Two trains travel from A to C via B. The speed of train 2 is double that of train 1 while traveling from A to B and their speeds are interchanged w

Question

The distance from B to C is thrice that from A to B. Two trains travel from A to C via B. The speed of train 2 is double that of train 1 while traveling from A to B and their speeds are interchanged w

Accepted Answer

Let $AB = d$ and $BC = 3d$. Let train 1’s speed from A to B be $v$. Then train 2’s speed from A to B is $2v$.

From B to C, the speeds are interchanged.

Time taken by train 1:
$\dfrac{d}{v} + \dfrac{3d}{2v} = \dfrac{5d}{2v}$
Time taken by train 2:
$\dfrac{d}{2v} + \dfrac{3d}{v} = \dfrac{7d}{2v}$

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