Calculate the relative rates of diffusion for 235UF6 and 238UF6 in gaseous form. Also if naturally occurring uranium ore having U235 and U238 in the ratio 0.72 and 99.28%, and if it is desired to enrich the U235 to 10% of the sample, making use of relative rates of diffusion of UF6 having U235 and U238 isotopes, how many diffusion stages are required?