We have calculated the mobility of electrons in n-type Mercury Cadmium Telluride (MCT) and compared it to a calculation of the mobility of electrons in n-type Mercury Zinc Telluride (MZT) with nearly the same energy gap and with the same number of donors and acceptors. We also compared the results of the MZT calculation with experiment. We found for equivalent energy gaps that the mobilities in the two compounds (MCT, MZT) were nearly the same. The calculations for both MCT and MZT were based on the best set of material parameters that we could compile from the literature. Using these parameters, the comparison with experiment for MZT yielded good results. Since MZT is harder and structurally more stable with respect to Hg retention than MCT, the possibility of equivalent mobility for MCT and MZT is significant. This calculation is one of the first extensive calculations of the mobility of MZT, and we compared it with another which appeared to be less extensive. Our calculation involves scattering of the electrons by longitudinal optic phonons, acoustic phonons, ionized impurities, holes, and compositional disorder. Since not all of these interactions can be approximated by elastic scattering, the corresponding Boltzmann equation was solved by a variational principle. We also discuss directions for future work.