The money paid by Party A accounts for one-third of the total number of other three people, so Party A accounts for 1/4 of the total number of four people (if the other three people are regarded as three, and Party A accounts for one, then four people are four). Similarly, B accounts for 1/5 of the total number of four people and C accounts for 1/6 of the total number of four people. So, Ding accounted for four people.

1- 1/4- 1/5- 1/6=23/60.

The contribution amount of D is 120×(23/60)=46 (ten thousand yuan).