I want to find all subsets which the total of elements is the same.
For example, Subsets[Range[30], {5}] means all 5-element subsets and the range of each element is from 0 to 30. But I want to get the subsets which are only the total of elements equals to 30 (e.g., {6, 6, 6 ,6, 6}, {7, 5, 6, 6, 6}, ....