On December 1, Kate Holmes opened a speech and hearing clinic. During December, her firm had the following transactions involving revenue and expenses.

Paid $3,100 for advertising. Provided services for $2,800 in cash. Paid $800 for telephone service. Paid salaries of $2,600 to employees. Provided services for $3,000 on credit. Paid $450 for office cleaning service.

Did the firm earn a net income or incur a net loss for the period? What was the amount?