00:01
A delacetessen is open 24 hours a day every day of the week.
00:04
On average, 24 orders are received by fax every two hours throughout the day.
00:08
Find the probability that a fax order will arrive within the next 11 minutes.
00:19
So the first thing we need to know is that lambda is 24.
00:24
And since we're dealing with minutes instead of hours, i'm going to say 24 divided by 120 minutes.
00:32
That would be two hours.
00:34
So 0 .167.
00:37
So the probability that x is less than or equal to 11 is 1 minus e to the negative 11th power times 0 .167, which is 0 .8407.
00:53
The probability that the time between two faxed orders will be between 4 and 5 minutes.
01:02
So let's go ahead and make that inclusive.
01:06
So that's going to be e to the negative 0 .5 .5.
01:18
4 times 1 .6, oops, not 1 .167, minus e to the negative 5 times 0 .167, which will be 0 .5127 minus 0 .4339...