Mixing = density change

Paul

Mixing = density change.

Say I have two substances A and B of different densities.

If I mix them (50% each by volume) I can calculate the total mixture density by considering a 1m^3 sample and calculate the mass of each present.

Equally, if I mix them (50% each by mass) I can calculate the mixture density by considering a 1kg sample and calculate volumes of each needed.

My question is what if A is at a temperature of 300K and B at a temperature of 1000K. How do I calculate the final density of the mixture in this case? And what about the final temperature?

What equations must I use and how do I use them?

Thankyou for any help.