Answer: 0.3679
Step-by-step explanation:
The cumulative distribution function for exponential distribution is :-
, where
is the mean of the distribution.
Given : A mean length of waiting time equal
minutes
i.e. Mean number of calls answered in a minute 
Now, the proportion of callers is put on hold longer than 2.8 minutes is given by :_

Hence, the proportion of callers is put on hold longer than 2.8 minutes = 0.3679
<h2>
Answer:</h2>
The last answer - 9x squared y squared
<h2>
</h2>
$13.52-$2=$11.52

Kareem was billed for 96 minutes.
Hope this helps. - M
<h3> Answer:</h3><h2>a.215</h2>
I don't know in letter b.
#CaRRyOnLeArniNG

keep in mind that, a negative coefficient to "x", will make the graph reflect over the y-axis.