NAME__________________________
3/5/2004
1
1.
[20 points]
A small accounting firm does not own computing facilities. It leases hardware
and software on an hourly usage basis from Arthur Enron, Inc (AEI). The firm must plan its
computing budget carefully and hence has studied its weekly usage of AEI’s computers. Suppose
the weekly usage X (in hours) has the following probability density function (pdf)
<
≤

<
≤
=
otherwise
x
x
x
x
x
f
,
0
10
5
),
10
(
25
1
5
0
,
25
1
)
(
(i)
[5 points]
Find the probability that the firm’s usage of AEI’s computers next week
will be at most 8 hours.
(ii)
[5 points]
Find the probability that the firm’s usage of AEI’s computers next week
will be between 4 and 8 hours?
(iii)
[10 points]
Suppose that AEI charges the firm $200/hour for hardware and software
usage, but the minimum amount billed in a week is $800, irrespective of the time
used. Express the weekly bill amount for computer usage as a function of X, and find
the expected amount of money that the firm spends each week for leasing computing
facilities from AEI.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document