Answer:
0.4
Step-by-step explanation:
To calculate the probability that a maintenance operation will take more than 2 hours and 15 minutes. We can first calculate the probability that ALL maintenance operation on 70 of the units will take less than 2 hours and 15 minutes, then subtract it from 1.
So the probability of a maintenance operation that would take less than 2 hours and 15 minutes, or 135 minutes is:
So the probability that a maintenance operation will take more than 2 hours and 15 minutes is:
