11 thoughts on “Singles – 8

  1. Sorry J, but didnt understand the logic 😦
    Can you elaborate it in a different way?

    Thanks for sharing though!

  2. Suppose I have 20 litres of type A and 50 litres of type B. I mix them all together. What will be the resultant mixture? Would you agree that it will have 70 litres and 2/7th of it will be Aand 5/7th will be B? Now, if I split it again into two parts, one of them being 20 litres and the other 50. The amount of type B in the first will be 5/7th of the 20 litres, right? (and similarly the amount of type A in the second will be 2/7th of 50 litres). That is all I am using…

  3. in some mock test there was a similar question (220 lit and 180 lit.), which i had solved using average property. but now i came to know of this simple way (xy/x+y).. it will be of great help if you start posting 2 post per day(minimum). there is not much time left. And you can leave vocab if you want to…..

  4. Anand, I do have a job to do as well, you know 🙂 Posting one post a day is itself a difficult task right now – typically takes 2-3 hours per post. And there are others for whom maths is fine and english is a tension, so vocab is also important…


    • ok fine.. i can understand.. what i was meant was your shortcuts are really awesome and we need more of that..

      • Believe me, I am doing my best 🙂 But I am looking at it as a long-term project…not just aimed at CAT-13 but as a longer-term repository of good questions/solutions/approaches…so would rather do a slow but good job than a hasty improvisation which serves the purpose neither of the present nor the future. Have been contemplating this blog idea for three years, only took the plunge this year because till now I wasn’t confident that I would be able to do justice to even one post a day.


  5. I am feeling the itch of not being able to interpret your solution despite tries. 😳
    When you say that “..at the end each of the two containers should also hold 40:60 ratio.”

    Thing is why are we thinking of mixing ” whole” of A and B. Shouldn’t be when Q litres of A mixed with 60 litres of B and vice versa..we will have different ratio in the containers at the end (and not 40:60).

    Sorry, if i missing something very basic here. Thanks 🙂

    • That’s because the question says that both containers now contain milk having the same price per litre…which means they both contain the two qualities in the same ratio!


  6. J, Please help me with this question. I did it in the longest possible way during the test, however, the it has a single line solution.

    The conc. of oragneade in the 72 litres of orangeade-water solution is 40%. Initially, 4lts of solution is replaced with water to form solution B. Then, 6 lts of solution B is replaced with water to form solution C. What is the conc. of orangeade in solution C?

    Solution: 40%(1-4/72)(1-6/72).

    Please help!

    • Just revise the concept of iterative alligation; it is directly being applied here! If we remove 1/10 of the solution, the original gets multiplied by (1-1/10) = 9/10. Also, this probably isn’t really the best place to ask doubts from outside the blog? 🙂


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