Calculate the effective charge number Zeff for a future tokamak, in which the deuterium density is np = 5 x 1019m-3, the tritium density is n = 5 x 1019m-3, the Beryllium density is nge = 1018m-3, and the Tungsten density is nw = 1016m-3. Assume that the ions are fully ionized (Beryllium charge is ZBe = 4 and Tungsten charge Zw 74), and there is no other ion species. When you calculate the electron density, use the quasi-neutrality.