Lei Mai Enterprises aids Singaporian students upon arrival in the United State. Paid by the United State Government. Lei Ma collects some service revenue in advance. In order cases he receives cash after performing relocation services. At the end of Augusts - a particularly busy period- Lei Ma's book showw the following:

                                                                       July 31           August 31

Accounts receivable                                      $1900              $2200

Unearned Service revenue                            $1200               $300

During August Lei Ma Enterprises received cash of $6100 from the Singaporian government. How much service revenue did the business earn during August?

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