Little's Law $1$ Consider the emergency department of a hospital that operates as follows: Upon arrival, patients first wait in line for registration. Then, after registration, patients wait to see a triage nurse who classifies them as either critical or non$-$critical. After the triage nurse, critical patients go to the emergency care area waiting to be seen by a doctor while non$-$critical patients go to the routine care area where they wait to see a doctor: It is determined that there are, on average, $10$ patients registering or waiting to be registered, $40$ patients being seen or waiting to be seen by the triage nurse, $30$ critical patients being seen or waiting to be seen by a doctor in the emergency area, and $20$ non$-$critical patients being seen or waiting to be seen by a doctor in the routine care area. Every hour $40$ patients arrive and $60\%$ of these patients are non$-$critical. Then, on average, how many minutes does a patient spend in the emergency department? Fin in the blanik