5) Dan and Joan were able to clean the attic in 7 hours together, It takes Joan 9 hours to complete the same job alone. Without help, how long
would it take Dan to complete the same job?

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable