please show all numeric work, thank you!! tha

answer is supposed to be around 0.6703% but i

figure out how to get that.

1. To increase hardness of steel gear, it was carburized at 1020C by introducing 1.3%C at its steel surface. What will be the final carbon content 0.0014 m beneath the surface if this treatment was lasted for 18 hours. The initial carbon content of steel is 0.2%C. (gas constant is 8.31 J/mol K)