JEE Main 2018 — Nuclear Physics Question with Solution

A solution containing active cobalt ${}_{27}{}^{60}\mathrm{Co}$ having an activity of $0.8 \mathrm{\mu Ci}$ and decay constant $\lambda$ is injected in an animal's body. When $1\mathrm{ c}{\mathrm{m}}^3$ blood is drawn from the animal's body after $10 \mathrm{h}$ of injection, the activity was found to be $300 \mathrm{dpm}$(decays per minute), then the total volume of blood in the animal's body is close to $[1 \mathrm{Ci}=3.7\times {10}^{10} \mathrm{dps}$(decays per second) and at $t=10 \mathrm{h}$ the value of ${\mathrm{e}}^{-\lambda t}=0.84]$