As a well established astronomer and physicist (Seperately!), I can't just give you the answer. Use the example below to guide you in the right direction.
As a simple example, consider the nearby visual binary-star system made up of the bright star Sirius A and its faint companion Sirius B. Their orbital period is 50 years and their orbital semimajor axis is 20 A.U.—7.5'' at a distance of 2.7 pc—implying that the sum of their masses is 3.2 times the mass of the Sun. Further study of the orbit shows that Sirius A has roughly twice the mass of its companion. It follows that the masses of Sirius A and Sirius B are 2.1 and 1.1 solar masses, respectively.
Maybe that will help you out.
Also, MattDamnit couldn't estimate the mass of his own ***, don't listen to him.
Oh, and sorry about the "further study" part. That's up to you to know what to do there.