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Founder at Durofy. Blogs on technology & startups, runs a full service digital agency, teaches AP Calculus.


  1. A single weight which is equally massive as the heavy ball or the other balls. or we can simply compare the balls among themselves rather than a weight

  2. 5565/3=1855
    so there will be 3 grps of 1855,so 2 comparisons
    then 1855/5=371
    so 5 grp of 371 so 4 comparisons required
    6 comparisons r required
    53 a prime no can be further divided so 52 comparisons required total=2+4+6+52=64

  3. How did you get 65? Try doing the question for 6 balls, 9 balls, and so on. You should find a pattern. The answer would the number of groups of 3 the total balls can be divided in.