sayan640
MartyMurray Bunuel GMATNinja KarishmaB , Can you please provide a solution to this question ?
It is a relative speed problem in a different context, that is all. You don't need to solve it once you can picture it as a relative speed problem. You would just know that you can solve it using statement 1 alone.
If I give you the following, will you be able to solve it?
Lisa and Paul start from 2 opposite ends of a path. The length of the path is 18 metres.
Lisa is covering 1 metre per 2x mins and Paul is covering 1 metre per 3x mins. After how many metres will they meet?Can you solve it? Sure. Do you need to, no. But if you were required to, this is how you would:
Time taken to meet = \(\frac{18}{Relative Speed} = \frac{18}{(1/2x + 1/3x)} = \frac{18*6x}{5}\)
Distance covered by Lisa in this time =\(\frac{18*6x}{5} * \frac{1}{2x} = 10.8 meters \)
So Lisa has covered 10 complete metres and is now covering the 11th metre when she meets Paul.
or simply use Ratio of their speeds is 3:2 and carry on from there. You can avoid using x completely then.
In our original question, this is exactly the data we have using statement 1 alone. Each metre is just each room.
She is in the 11th room which is K and hence statement 1 alone is sufficient.
Statement 2 alone does not give us the ratio of their speeds or time taken, just the difference in the time taken so we cannot solve using this data.
Answer (A)
It is similar to other such problems that also use relative speed in different contexts. For example,
Two jars - one full of water with a drain and other empty with a faucet. When will both have the same level of water?