An fcc iron-carbon alloy initially containing 0.20 wt% c is carburized at an elevated -1 and temperature (semi-infinite diffusion) where the diffusivity is 2 x 10-15 cm2sec in an atmosphere wherein the surface carbon concentration is maintained at 1.1 wt%. at what depth is the carbon concentration equal to 0.3612 wt% if the process time was 24 hours