A logistics company tracks the number of its heavy-duty trucks that require unscheduled maintenance each day. Based on historical data, the number of such trucks per day can be modeled by a Poisson distribution with a mean of 2.4.
the probability that on a given day, exactly 3 heavy-duty trucks require unscheduled maintenance.
The company expands its fleet by adding medium-duty trucks. The number of medium-duty trucks requiring maintenance per day also follows a Poisson distribution, with a mean of maintenance requests per truck per day. Maintenance events for all trucks are assumed to be independent.
the minimum total number of trucks in the fleet (the existing heavy-duty fleet plus medium-duty trucks) such that the probability of having more than 15 maintenance requests in a single day is at least 0.15.