Answer:
The probability that the demand will exceed 190 cfs during the early afternoon on a randomly selected day is 
Step-by-step explanation:
Let Y be the water demand in the early afternoon.
If the random variable Y has density function f (y) and a < b, then the probability that Y falls in the interval [a, b] is

A random variable Y is said to have an exponential distribution with parameter
if and only if the density function of Y is

If Y is an exponential random variable with parameter β, then
mean = β
To find the probability that the demand will exceed 190 cfs during the early afternoon on a randomly selected day, you must:
We are given the mean = β = 100 cubic feet per second

Compute the indefinite integral 

Compute the boundaries


The probability that the demand will exceed 190 cfs during the early afternoon on a randomly selected day is 