Challenge yourself! – Grades 7-8 (Arithmetic sequence sums)

The sum of an arithmetic sequence from its $300\textsuperscript{th}$ term through its $399\textsuperscript{th}$ term is $8000$ , while the sum from its $500\textsuperscript{th}$ term through its $549\textsuperscript{th}$ term is $21500$ . What is the sum of the sequence from its $200\textsuperscript{th}$ term through its $249\textsuperscript{th}$ term?