cannot seem to figure this out

On March 12, Medical Waste Services provides services on account to Grace Hospital for $11,000, terms 2/10, n/30, Grace pays for those services on March 20 . Requlred: For Medical Waste Services, record the seryice on occount on March 12 and the collection of cash on March 20 . If no entry is required for a porticular transaction/event, select "No Journal Entry Requlred" In the first account fleid.)