Drug Metabolism Markov Model

Researchers are investigating a new drug "examenol" and have discovered the following

about its metabolization:

Each hour $20\%$ of examenol changes to metabolite A and $10\%$ changes to

metabolite B$.$ Another $10\%$ is excreted.

Each hour $30\%$ of metabolite A changes to metabolite B and $30\%$ of metabolite $A$ is

excreted.

Each hour $40\%$ of metabolite B changes to metabolite A and $10\%$ of metabolite B is

excreted.

Determine the number of hours it takes for $60\%$ of one dose of examenol to be

excreted.

Hint: The metabolization can be modeled using a Markov chain with four states

$($examenol$,$ metabolite A$,$ metabolite B$,$ excreted$).$ At the beginning, all dosage is in the

examenol state.

Your code snippet should define the following variables: