.
Step by step.
1. You calculate exceed for each person.
2. You exclude Charles from consideration, since his figure is below the basic quota (which means that his bonus is zero);
3. Next you make long proportion for exceeds of the three remaining members.
4. Finally, you distribute $10000 between A, B and D according to this long proportion.
The last step is similar to what I presented to you in my previous solution/post at the link
https://www.algebra.com/algebra/homework/Systems-of-equations/Systems-of-equations.faq.question.1165272.html
https://www.algebra.com/algebra/homework/Systems-of-equations/Systems-of-equations.faq.question.1165272.html