The manager of a fast-food restaurant determines that the average time that her customers wait for service is 1.5 minutes. (a) Find the probability that a customer has to wait more than 4 minutes. (Round your answer to three decimal

0.069 = 6.9% probability that a customer has to wait more than 4 minutes.

Step-by-step explanation:

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

In which is the decay parameter.

The probability that x is lower or equal to a is given by:

Which has the following solution:

In this problem, we have that:

So

Find the probability that a customer has to wait more than 4 minutes.

Either the customer has to wait 4 minutes or less, or he has to wait more than 4 minutes. The sum of the probabilities of these events is decimal 1. So

We want P(X > 4). So

0.069 = 6.9% probability that a customer has to wait more than 4 minutes.

the perimeter is increased by a factor of 2