CMD for four isochrones plotted using data from the Padova evolutionary tracks. The stellar evolutionary tracks are as follows; 2 Gyr (TRGB K = 17.86 mag) and 10 Gyr (TRGB K = 17.47 mag) at Z = 0.002 (~NGC 6822; this work with an adjustment for the presumed abundance excess of α-elements based on the work of Ryan & Norris 1991), and for Z = 0.002 (SMC; Maeder et al. 1999) (TRGB K = 17.52 mag) and Z = 0.007 (LMC; Maeder et al. 1999) (TRGB K = 17.03 mag) at an age of 7 Gyr. The crosses mark the position of the TRGB for each isochrone and the horizontal line marks the position of the TRGB magnitude used in this study. The average of several [Fe/H] measurements of the LMC and the SMC have been used for convenience.