A freshly prepared sample of iodine-131 contains 6.0×1020 undecayed nuclei. The half-life of iodine-131 is 8.0 days.
(i) Calculate the decay constant of iodine-131.
(ii) Determine the number of iodine-131 nuclei that will remain undecayed after 24 days.
(iii) Express the result of part (ii) as a percentage of the initial number of nuclei.