Using the exponential distribution, it is found that there is a 0.4462 = 44.62% probability that a customer waits less than 39 seconds.
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, <u>mean of 66 seconds</u>, hence, the decay parameter is:

The probability <u>that a customer waits less than 39 seconds</u> is:

0.4462 = 44.62% probability that a customer waits less than 39 seconds.
A similar problem is given at brainly.com/question/17039711