I'm confused on question (f), I posted part e question and answer as reference

A monodirectional beam of 0.0253 eV neutrons strikes a slab of heavy water (D2O) at a right angle. The total microscopic cross sections of deuterium and naturally occurring oxygen at this energy are 4.92 b and 3.76 b, respectively. The absorption cross sections of deuterium and naturally-occurring oxygen at this energy are 0.52 mb and 0.27 mb, respectively. (f) What is the probability that a neutron in the incident beam interacts in the slab thickness obtained in part e. What is the probability that a 0.0253 eV neutron that interacts in the slab is absorbed in its first interaction?

Part e for reference only. (e)How thick must the slab be to reduce the intensity of the uncollided beam by a factor of 10 (answer from part e is 5.105)