A cancer patient is undergoing radiation therapy in which protons with and energy of 1.2MeV are incident

Question:

A cancer patient is undergoing radiation therapy in which protons with and energy of 1.2MeV are incident on a 0.25-kg tumor.
(a) If the patient receives an effective does of 1.0rem, what is the absorbed does?
(b) How many protons are absorbed by the tumor? Assume QF ≈ 1.