Question 1180931
<br>
For part a, I will disagree with tutor @ikleyn.  Since the distribution is uniform between 10 and 120 minutes, I interpret that to mean the probability of having the diagnosis complete in less than 10 minutes is 0.<br>
Therefore the diagnosis times that are less than 30 minutes are between 10 and 30 minutes instead of between 0 and 30 minutes.  That makes the probability in this case 20/110 = 2/11.<br>