By measuring time-resolved fluorescence signals, we have obtained radiative lifetimes and total cross sections for collisional deactivation by He, Ne, and Ar of K n S-2 and (n-2)D-2 states (n=7-11). The radiative lifetimes obtained agree with those previously reported. The cross sections, in the range of 15-180 Angstrom(2), generally increase with increasing the principal quantum number. Their magnitudes for the n S-2 and (n-2)D-2 states are similar. The results are closely related to the geometric size of the excited K states, and weakly dependent on their orbital angular momentum. Our case differs from the K*-H-2, collision, in which the electron harpoon mechanism should be involved. Our case also differs from the collision of Na* with rare gas; the latter easily induces l-mixing (l greater than or equal to 2) of the same n. We have also found that the relative efficiency for He and Ar is different in quenching of the low-lying and the high-lying K states. When n is small, the total cross section of deactivation by He collision is larger than that by Ar collision, but is reversed for the high-lying states. Detailed discussion on these phenomena is presented.