Your question is too vague. What properties? What fluids? Reactive or non-reactive mixtures? Which formulas? I wrote a book on azeotropes, which is a special type of mixture: one that is not easily separated.

Any type of gas mixtures which shows flow properties-cryogenic fluids,syn- gases-hydrogen, neon and others.comming to properties like all the physical properties of the overall gas mixture.

For gas mixtures, Dalton's law together with the perfect gas law tell us that at constant temperature and constant total pressure, the variation of the concentrations of a gaseous mixture results in a change in the partial pressure of each gas component.

See for example:

Smith, W. R., & Missen, R. W. (2005). A note on Dalton's law: Myths, facts, and implementation. Journal of chemical education, 82(8), 1197. Available on:

https://pubs.acs.org/doi/pdf/10.1021/ed082p1197?casa_token=MjqdS3AEVZQAAAAA:1aDpxQDjw2--e0m5XveYgU7McfYAC9EYc3cqfoM_Vsa9-HYoZRHtBLy22_hQZwB5gml2GofJ0xvy_yYA

If you look in Perry, Chemical Engineers Handbook, you will find the equations for the calculation of most types of mixture properties.