A small amount of solution containing `.^(24)Na` radionuclide with activity `A=2xx10^(3)` dis/sec. was injected in the blood stream of a man. The activity of `1 cm^(3)` of blood sample taken `t=5` hrs later turned out to be `A'=16"dis/min/cm"^(3)`. The half life of radionuclide is `T=15` hrs. Find the volume of the man's blood.