Physics/astronomy eclipsing binary problem help

[Soylentgreen]

physics/astronomy eclipsing binary problem! help!

I have been looking at this problem for a while and i am really getting frustrated.

Here it is. I have an eclipsing binary system with a period of 1 year. Star Q has 800 solar luminosities, while the other star, star R, has 5 solar luminosities.
the radius of star R is 1,000,000 km, and it is .75 solar masses. Its apparent magnitude is 11.6.
It does not say whether or not the stars are main sequence.

a) what is the apparent magnitude of star R?
b) what is the separation of the two stars in km
c) what is the distance to the star system in parsecs.
d) what is the absolute magniude of star R.the answer for the above questions are as follows:
a) 5.8-6.3
b) 7-8x 10^9 km
c) 470-530 parsecs
d) 2.8-3.4

i have the answers but i don't know how to get to them and i have been trying for over an hour and a half. please help someone!

 

[denverdoc]

probably not the best place to post this problem.