Problem Solving (PS) | Re: 12 Days of Christmas GMAT Competition - Day 6: Two trains, A and B

Let's denote the speed of train B as b and the speed of train A as 2b.
When two objects are moving toward each other, their relative speed is the sum of their individual speeds. So, the relative speed of A and B is (2b + b)= 3b.

Let t be the time they take to meet, and d be the distance between stations X and Y.

The distance traveled by train A is (2b * t) and by train B is (b * t).

Given that when they meet, the slower train (B) has traveled 30 km less than the faster train (A), we can set up the equation:
2b*t = b*t +30

Now, we can solve for t:

t = 30/b

Substitute this back into the expression for the distance traveled by train A:

2b * t = 2b * 30/b = 60

Similarly the distance travelled by B is 30 km.

So, the distance between stations X and Y is 90 km.

The correct answer is 90 km.

Statistics : Posted by SushantPaudel • on 18 Dec 2023, 06:00 • Replies 13 • Views 146

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