Given the task definition and input, reply with output. You are given a math word problem and you are supposed to apply a single mathematical operators like addition, subtraction, multiplication or division on the numbers embedded in the text to answer the following question and then only report final the numerical answer.

A lawyer bills her clients 200 dollars per hour of service . If a client 's case requires 39 hours to complete , use proportion to calculate how much the client will owe the lawyer in dollars .

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
7800