Answer:
And if we solve for a we got
Eighty percent of the time, it takes more than 8.526 how many minutes to find a parking space
Step-by-step explanation:
Let X the random variable that represent the lenght of time it takes to find a parking space of a population, and for this case we know the distribution for X is given by:
Where and
For this part we want to find a value a, such that we satisfy this condition:
(a)
(b)
We want to find a value who accumulate 0.80 of the area on the left and 0.2 of the area on the right it's z=0.842.
If we use condition (b) from previous we have this:
Using this formula we have:
And if we solve for a we got
Eighty percent of the time, it takes more than 8.526 how many minutes to find a parking space