Chapter 9 linear inequaliTieS 323
Let x = number of hours per year the equipment is used
The monthly purchase costs amount to 12(2500) = 30,000 dollars annually.
The annual purchase cost = 30,000 + 20x.
Purchasecost<Rentcost
+<
30 000 20 45 000
30 000
,,
,
x
--
<
≤
<
30 000
20 15 000
15 000
20
750
,
,
,
x
x
x
The equipment should be used less than 750 hours annually to justify pur-
chasing it rather than renting it.
An amusement park sells an unlimited season pass for $240. A daily ticket
sells for $36. How many times would a customer need to use the ticket in
order for the season ticket to cost less than purchasing daily tickets?
Let x = number of daily tickets purchased per season
36 x = daily ticket cost
Seasonticketcost<dailyticketcost
240 36
24
< x
00
36
(^623)
<
<
x
x
A customer would need to use the ticket more than 623 times (or 7 or more
times) in order for the season ticket to cost less than purchasing daily
tickets.
Bank A offers a 621 % certificate of deposit and Bank B offers a 534 % cer-
tificate of deposit but will give a $25 bonus at the end of the year. What is
the least amount a customer would need to deposit at Bank A to make
Bank A’s offer no less attractive than Bank B’s offer?
Let x = amount to deposit
If x dollars is deposited at Bank A, the interest at the end of the year would
be 0.065x. If x dollars is deposited at Bank B, the interest at the end of