In terms of increasing number of candies received, the possible sequence can be:
either Mohan < Ram < Raja < Roy
or Mohan < Ram < Roy < Raja
The above order clearly shows that Ram receives at least 2 candies. Possible sets for candies received by Ram and Roy will be (2, 6) and (3, 7).
Note: The case (4, 8) etc. are not possible as then the other two values will become less than 4 each.
S ubsequently only possible sets for overall distribution are:
Thus, Raja can have 7 or 5 or 4 candies.
∴Maximum possible difference = 7 - 4 = 3