Now we are to find the probability of receiving 10 calls in a 20-minute interval. It is given that, on average, 36 calls are received per hour, so this must be converted to a 20-minute interval. We previously found that, on average, there are 0.6 calls per minute. To find the mean number of calls in a 20-minute interval, multiply the mean number of calls per minute by 20. (20 minutes)(mean number of calls per minute) = 20 0.6 20(0. 12 Thus, on the same 20-minute time interval, we have = 0.6 ) calls per 20 minutes and x = Submit Skip (you cannot come back) Need Help? Read It Submit Answer