Kshitij, consider that at the start B and C must have been together. So if after B completes 10 m he is x m ahead, after 20 m he will be 2x m ahead and so on. So if when B is at the end of the race he leads by 21, and at some point in between he leads by 14, at that point he must have covered 14/21 = 2/3 of the race.
However at that point he is also 20 m from the finish as A has just won at that moment, and A is 20 m ahead of him. So 1/3rd of the race must be 20.
but sir, i have one doubt here, since B was leading C by 14 meters, then C was also moving at that time and when B finished, C moved further, the point is C must have covered some distance of total length from starting point, and what we are considering in this question is the 14 meters(2/3 rd distance relative to C) distance between B and C, but there must have been some distance before it too.. so can we conclude that answer should have been greater than 60 (if none of these were not there)..?
Vaibhav, I am deliberately giving minimalistic explanations for these. The whole point is to induce (even incite) you to think, not to give you yet another “formula” 🙂 After all, the same question will not come in the exam, it is the approach I am aiming to inculcate here. I am writing down, roughly, what are the thoughts that go through my head when I attack such a problem. Ideally, after thinking about it for a while, you will also be able to figure out what I did in each case…..and try to apply such processes to every problem you encounter.
Dear J sir, i have a question related to Q2
I had to attach a pic to ask that :http://imgur.com/UdlCqJV
Can i do it in somewhat weighted averages way?
I want to split the 12 rs which were paid extra to yield a profit of 30%
Can i split the 12 using ratios, so that i can get CP – SP and New SP – CP whose sum is 12?
I think the pic will tell you what i’m thinking and asking for. 🙂
Regards,
Kartik
CAT-holics 
Sir, cudnt understand the logic behind the solution of first ques..pls help!!
Kshitij, consider that at the start B and C must have been together. So if after B completes 10 m he is x m ahead, after 20 m he will be 2x m ahead and so on. So if when B is at the end of the race he leads by 21, and at some point in between he leads by 14, at that point he must have covered 14/21 = 2/3 of the race.
However at that point he is also 20 m from the finish as A has just won at that moment, and A is 20 m ahead of him. So 1/3rd of the race must be 20.
regards
J
but sir, i have one doubt here, since B was leading C by 14 meters, then C was also moving at that time and when B finished, C moved further, the point is C must have covered some distance of total length from starting point, and what we are considering in this question is the 14 meters(2/3 rd distance relative to C) distance between B and C, but there must have been some distance before it too.. so can we conclude that answer should have been greater than 60 (if none of these were not there)..?
Er. Read carefully. The 14 was before, the 21 was later. In between B gained extra 7.
regards
J
yes that is fine but C was not stationary while A won.. I am just concerned about the distance C might have traveled before that?
That will also be in proportion to the time taken till then, for both B and C.
regards
J
I had the same doubt as Kshitij, you explained it much better here, really cleared it up and I understood the logic. Thanks
Vaibhav, I am deliberately giving minimalistic explanations for these. The whole point is to induce (even incite) you to think, not to give you yet another “formula” 🙂 After all, the same question will not come in the exam, it is the approach I am aiming to inculcate here. I am writing down, roughly, what are the thoughts that go through my head when I attack such a problem. Ideally, after thinking about it for a while, you will also be able to figure out what I did in each case…..and try to apply such processes to every problem you encounter.
Dear J sir, i have a question related to Q2
I had to attach a pic to ask that :http://imgur.com/UdlCqJV
Can i do it in somewhat weighted averages way?
I want to split the 12 rs which were paid extra to yield a profit of 30%
Can i split the 12 using ratios, so that i can get CP – SP and New SP – CP whose sum is 12?
I think the pic will tell you what i’m thinking and asking for. 🙂
Regards,
Kartik
And this i’m asking so that I can get an idea, how much more money is to be increased to get into the profit zone
Yes that would also give the answer. It will tell you that the 20% loss is 4.8…
regards
J