Each plate has to get atleast 7 cookies ,all the plates should have the same number of cookies and also the number of plates must be greater than or equal to 2.
If we take 2 plates , there can be 21 cookies in each.
If we take 3 plates , there can be 14 cookies in each.
If we take 6 plates , there can be 7 cookies in each.
These are the 3 possible cases.
Since there cannot be broken pieces, no other combination is possible.
